Internet group management protocol (IGMP) of a layer-2 network in a virtualized cloud environment

ABSTRACT

Techniques are described for communications in an L2 virtual network. In an example, the L2 virtual network includes a plurality of L2 compute instances hosted on a set of host machines and a plurality of L2 virtual network interfaces and L2 virtual switches hosted on a set of network virtualization devices. An L2 virtual network interface emulates an L2 port of the L2 virtual network. IGMP configuration is distributed to the L2 virtual switches.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit and priority under 35 U.S.C.119(e) of U.S. Application No. 63/132,377, filed on Dec. 30, 2020,entitled “LAYER-2 NETWORKING IN A VIRTUALIZED CLOUD ENVIRONMENT,” thecontent of which is herein incorporated by reference in its entirety forall purposes.

BACKGROUND

Cloud computing provides on-demand availability of computing resources.Cloud computing can be based on data centers that are available to usersover the internet. Cloud computing can provide Infrastructure as aService (IaaS). A virtual network may be created for use by users.However, these virtual networks have limitations that limit theirfunctionality and value. Accordingly, further improvements are desired.

BRIEF SUMMARY

The present disclosure relates to virtualized cloud environments.Techniques are described for providing Layer 2 networking functionalityin a virtualized cloud environment. The Layer 2 functionality isprovided in addition to and in conjunction with Layer 3 networkingfunctionality provided by the virtualized cloud environment.

Some embodiments of the present disclosure relate to providing a Layer 2virtual local area network (VLAN) in a private network to a customer,such as a virtual cloud network (VCN) of the customer. Different computeinstances are connected in the Layer 2 VLAN. The customer is given theperception of an emulated single switch that connects the computeinstances. In fact, this emulated switch is implemented as an infinitelyscalable distributed switch that includes a collection of localswitches. More specifically, each compute instance executes on a hostmachine connected to a network virtualization device (NVD). For eachcompute instance on a host connected to an NVD, the NVD hosts a Layer 2virtual network interface card (VNIC) and a local switch associated withthe compute instance. The Layer 2 VNIC represents a port of the computeinstance on the Layer 2 VLAN. The local switch connects the VNIC toother VNICs (e.g., other ports) associated with other compute instancesof the Layer 2 VLAN. Various Layer 2 network services are supportedincluding, for instance, Internet Group Management Protocol (IGMP)functionalities.

Various embodiments are described herein, including methods, systems,non-transitory computer-readable storage media storing programs, code,or instructions executable by one or more processors, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a high level diagram of a distributed environment showing avirtual or overlay cloud network hosted by a cloud service providerinfrastructure according to certain embodiments.

FIG. 2 depicts a simplified architectural diagram of the physicalcomponents in the physical network within CSPI according to certainembodiments.

FIG. 3 shows an example arrangement within CSPI where a host machine isconnected to multiple network virtualization devices (NVDs) according tocertain embodiments.

FIG. 4 depicts connectivity between a host machine and an NVD forproviding I/O virtualization for supporting multitenancy according tocertain embodiments.

FIG. 5 depicts a simplified block diagram of a physical network providedby a CSPI according to certain embodiments.

FIG. 6 is a schematic illustration of a computing network according tocertain embodiments.

FIG. 7 is a logical and hardware schematic illustration of a VLAN isaccording to certain embodiments.

FIG. 8 is a logical schematic illustration of multiple connected L2VLANs according to certain embodiments.

FIG. 9 is a logical schematic illustration of multiple connected L2VLANs and a subnet 900 according to certain embodiments.

FIG. 10 is a schematic illustration of intra-VLAN communication andlearning within a VLAN according to certain embodiments.

FIG. 11 is a schematic illustration a VLAN according to certainembodiments.

FIG. 12 is a flowchart illustrating a process 1200 for intra-VLANcommunication according to certain embodiments.

FIG. 13 illustrates an example environment suitable to define an Layer 2virtual network configuration according to certain embodiments.

FIG. 14 illustrates an example IGMP technique in a Layer 2 virtualnetwork according to certain embodiments.

FIG. 15 is a flowchart illustrating a process for generating an IGMPtable in a Layer 2 virtual network according to certain embodiments.

FIG. 16 is a flowchart illustrating a process for updating an IGMP tablein a Layer 2 virtual network according to certain embodiments.

FIG. 17 is a flowchart illustrating a process for performing IGMPquerying in a Layer 2 virtual network according to certain embodiments.

FIG. 18 is a flowchart illustrating a process for using an IGMP table ina Layer 2 virtual network according to certain embodiments.

FIG. 19 is a block diagram illustrating one pattern for implementing acloud infrastructure as a service system, according to at least oneembodiment.

FIG. 20 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 21 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 22 is a block diagram illustrating another pattern for implementinga cloud infrastructure as a service system, according to at least oneembodiment.

FIG. 23 is a block diagram illustrating an example computer system,according to at least one embodiment.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, specificdetails are set forth in order to provide a thorough understanding ofcertain embodiments. However, it will be apparent that variousembodiments may be practiced without these specific details. The figuresand description are not intended to be restrictive. The word “exemplary”is used herein to mean “serving as an example, instance, orillustration.” Any embodiment or design described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother embodiments or designs.

A—Example Virtual Networking Architectures

The term cloud service is generally used to refer to a service that ismade available by a cloud services provider (CSP) to users or customerson demand (e.g., via a subscription model) using systems andinfrastructure (cloud infrastructure) provided by the CSP. Typically,the servers and systems that make up the CSP's infrastructure areseparate from the customer's own on-premise servers and systems.Customers can thus avail themselves of cloud services provided by theCSP without having to purchase separate hardware and software resourcesfor the services. Cloud services are designed to provide a subscribingcustomer easy, scalable access to applications and computing resourceswithout the customer having to invest in procuring the infrastructurethat is used for providing the services.

There are several cloud service providers that offer various types ofcloud services. There are various different types or models of cloudservices including Software-as-a-Service (SaaS), Platform-as-a-Service(PaaS), Infrastructure-as-a-Service (IaaS), and others.

A customer can subscribe to one or more cloud services provided by aCSP. The customer can be any entity such as an individual, anorganization, an enterprise, and the like. When a customer subscribes toor registers for a service provided by a CSP, a tenancy or an account iscreated for that customer. The customer can then, via this account,access the subscribed-to one or more cloud resources associated with theaccount.

As noted above, infrastructure as a service (IaaS) is one particulartype of cloud computing service. In an IaaS model, the CSP providesinfrastructure (referred to as cloud services provider infrastructure orCSPI) that can be used by customers to build their own customizablenetworks and deploy customer resources. The customer's resources andnetworks are thus hosted in a distributed environment by infrastructureprovided by a CSP. This is different from traditional computing, wherethe customer's resources and networks are hosted by infrastructureprovided by the customer.

The CSPI may comprise interconnected high-performance compute resourcesincluding various host machines, memory resources, and network resourcesthat form a physical network, which is also referred to as a substratenetwork or an underlay network. The resources in CSPI may be spreadacross one or more data centers that may be geographically spread acrossone or more geographical regions. Virtualization software may beexecuted by these physical resources to provide a virtualizeddistributed environment. The virtualization creates an overlay network(also known as a software-based network, a software-defined network, ora virtual network) over the physical network. The CSPI physical networkprovides the underlying basis for creating one or more overlay orvirtual networks on top of the physical network. The virtual or overlaynetworks can include one or more virtual cloud networks (VCNs). Thevirtual networks are implemented using software virtualizationtechnologies (e.g., hypervisors, functions performed by networkvirtualization devices (NVDs) (e.g., smartNICs), top-of-rack (TOR)switches, smart TORs that implement one or more functions performed byan NVD, and other mechanisms) to create layers of network abstractionthat can be run on top of the physical network. Virtual networks cantake on many forms, including peer-to-peer networks, IP networks, andothers. Virtual networks are typically either Layer-3 IP networks orLayer-2 VLANs. This method of virtual or overlay networking is oftenreferred to as virtual or overlay Layer-3 networking. Examples ofprotocols developed for virtual networks include IP-in-IP (or GenericRouting Encapsulation (GRE)), Virtual Extensible LAN (VXLAN—IETF RFC7348), Virtual Private Networks (VPNs) (e.g., MPLS Layer-3 VirtualPrivate Networks (RFC 4364)), VMware's NSX, GENEVE (Generic NetworkVirtualization Encapsulation), and others.

For IaaS, the infrastructure (CSPI) provided by a CSP can be configuredto provide virtualized computing resources over a public network (e.g.,the Internet). In an IaaS model, a cloud computing services provider canhost the infrastructure components (e.g., servers, storage devices,network nodes (e.g., hardware), deployment software, platformvirtualization (e.g., a hypervisor layer), or the like). In some cases,an IaaS provider may also supply a variety of services to accompanythose infrastructure components (e.g., billing, monitoring, logging,security, load balancing and clustering, etc.). Thus, as these servicesmay be policy-driven, IaaS users may be able to implement policies todrive load balancing to maintain application availability andperformance. CSPI provides infrastructure and a set of complementarycloud services that enable customers to build and run a wide range ofapplications and services in a highly available hosted distributedenvironment. CSPI offers high-performance compute resources andcapabilities and storage capacity in a flexible virtual network that issecurely accessible from various networked locations such as from acustomer's on-premises network. When a customer subscribes to orregisters for an IaaS service provided by a CSP, the tenancy created forthat customer is a secure and isolated partition within the CSPI wherethe customer can create, organize, and administer their cloud resources.

Customers can build their own virtual networks using compute, memory,and networking resources provided by CSPI. One or more customerresources or workloads, such as compute instances, can be deployed onthese virtual networks. For example, a customer can use resourcesprovided by CSPI to build one or multiple customizable and privatevirtual network(s) referred to as virtual cloud networks (VCNs). Acustomer can deploy one or more customer resources, such as computeinstances, on a customer VCN. Compute instances can take the form ofvirtual machines, bare metal instances, and the like. The CSPI thusprovides infrastructure and a set of complementary cloud services thatenable customers to build and run a wide range of applications andservices in a highly available virtual hosted environment. The customerdoes not manage or control the underlying physical resources provided byCSPI but has control over operating systems, storage, and deployedapplications; and possibly limited control of select networkingcomponents (e.g., firewalls).

The CSP may provide a console that enables customers and networkadministrators to configure, access, and manage resources deployed inthe cloud using CSPI resources. In certain embodiments, the consoleprovides a web-based user interface that can be used to access andmanage CSPI. In some implementations, the console is a web-basedapplication provided by the CSP.

CSPI may support single-tenancy or multi-tenancy architectures. In asingle tenancy architecture, a software (e.g., an application, adatabase) or a hardware component (e.g., a host machine or a server)serves a single customer or tenant. In a multi-tenancy architecture, asoftware or a hardware component serves multiple customers or tenants.Thus, in a multi-tenancy architecture, CSPI resources are shared betweenmultiple customers or tenants. In a multi-tenancy situation, precautionsare taken and safeguards put in place within CSPI to ensure that eachtenant's data is isolated and remains invisible to other tenants.

In a physical network, a network endpoint (“endpoint”) refers to acomputing device or system that is connected to a physical network andcommunicates back and forth with the network to which it is connected. Anetwork endpoint in the physical network may be connected to a LocalArea Network (LAN), a Wide Area Network (WAN), or other type of physicalnetwork. Examples of traditional endpoints in a physical network includemodems, hubs, bridges, switches, routers, and other networking devices,physical computers (or host machines), and the like. Each physicaldevice in the physical network has a fixed network address that can beused to communicate with the device. This fixed network address can be aLayer-2 address (e.g., a MAC address), a fixed Layer-3 address (e.g., anIP address), and the like. In a virtualized environment or in a virtualnetwork, the endpoints can include various virtual endpoints such asvirtual machines that are hosted by components of the physical network(e.g., hosted by physical host machines). These endpoints in the virtualnetwork are addressed by overlay addresses such as overlay Layer-2addresses (e.g., overlay MAC addresses) and overlay Layer-3 addresses(e.g., overlay IP addresses). Network overlays enable flexibility byallowing network managers to move around the overlay addressesassociated with network endpoints using software management (e.g., viasoftware implementing a control plane for the virtual network).Accordingly, unlike in a physical network, in a virtual network, anoverlay address (e.g., an overlay IP address) can be moved from oneendpoint to another using network management software. Since the virtualnetwork is built on top of a physical network, communications betweencomponents in the virtual network involves both the virtual network andthe underlying physical network. In order to facilitate suchcommunications, the components of CSPI are configured to learn and storemappings that map overlay addresses in the virtual network to actualphysical addresses in the substrate network, and vice versa. Thesemappings are then used to facilitate the communications. Customertraffic is encapsulated to facilitate routing in the virtual network.

Accordingly, physical addresses (e.g., physical IP addresses) areassociated with components in physical networks and overlay addresses(e.g., overlay IP addresses) are associated with entities in virtualnetworks. Both the physical IP addresses and overlay IP addresses aretypes of real IP addresses. These are separate from virtual IPaddresses, where a virtual IP address maps to multiple real IPaddresses. A virtual IP address provides a 1-to-many mapping between thevirtual IP address and multiple real IP addresses.

The cloud infrastructure or CSPI is physically hosted in one or moredata centers in one or more regions around the world. The CSPI mayinclude components in the physical or substrate network and virtualizedcomponents (e.g., virtual networks, compute instances, virtual machines,etc.) that are in an virtual network built on top of the physicalnetwork components. In certain embodiments, the CSPI is organized andhosted in realms, regions and availability domains. A region istypically a localized geographic area that contains one or more datacenters. Regions are generally independent of each other and can beseparated by vast distances, for example, across countries or evencontinents. For example, a first region may be in Australia, another onein Japan, yet another one in India, and the like. CSPI resources aredivided among regions such that each region has its own independentsubset of CSPI resources. Each region may provide a set of coreinfrastructure services and resources, such as, compute resources (e.g.,bare metal servers, virtual machine, containers and relatedinfrastructure, etc.); storage resources (e.g., block volume storage,file storage, object storage, archive storage); networking resources(e.g., virtual cloud networks (VCNs), load balancing resources,connections to on-premise networks), database resources; edge networkingresources (e.g., DNS); and access management and monitoring resources,and others. Each region generally has multiple paths connecting it toother regions in the realm.

Generally, an application is deployed in a region (i.e., deployed oninfrastructure associated with that region) where it is most heavilyused, because using nearby resources is faster than using distantresources. Applications can also be deployed in different regions forvarious reasons, such as redundancy to mitigate the risk of region-wideevents such as large weather systems or earthquakes, to meet varyingrequirements for legal jurisdictions, tax domains, and other business orsocial criteria, and the like.

The data centers within a region can be further organized and subdividedinto availability domains (ADs). An availability domain may correspondto one or more data centers located within a region. A region can becomposed of one or more availability domains. In such a distributedenvironment, CSPI resources are either region-specific, such as avirtual cloud network (VCN), or availability domain-specific, such as acompute instance.

ADs within a region are isolated from each other, fault tolerant, andare configured such that they are very unlikely to fail simultaneously.This is achieved by the ADs not sharing critical infrastructureresources such as networking, physical cables, cable paths, cable entrypoints, etc., such that a failure at one AD within a region is unlikelyto impact the availability of the other ADs within the same region. TheADs within the same region may be connected to each other by a lowlatency, high bandwidth network, which makes it possible to providehigh-availability connectivity to other networks (e.g., the Internet,customers' on-premise networks, etc.) and to build replicated systems inmultiple ADs for both high-availability and disaster recovery. Cloudservices use multiple ADs to ensure high availability and to protectagainst resource failure. As the infrastructure provided by the IaaSprovider grows, more regions and ADs may be added with additionalcapacity. Traffic between availability domains is usually encrypted.

In certain embodiments, regions are grouped into realms. A realm is alogical collection of regions. Realms are isolated from each other anddo not share any data. Regions in the same realm may communicate witheach other, but regions in different realms cannot. A customer's tenancyor account with the CSP exists in a single realm and can be spreadacross one or more regions that belong to that realm. Typically, when acustomer subscribes to an IaaS service, a tenancy or account is createdfor that customer in the customer-specified region (referred to as the“home” region) within a realm. A customer can extend the customer'stenancy across one or more other regions within the realm. A customercannot access regions that are not in the realm where the customer'stenancy exists.

An IaaS provider can provide multiple realms, each realm catered to aparticular set of customers or users. For example, a commercial realmmay be provided for commercial customers. As another example, a realmmay be provided for a specific country for customers within thatcountry. As yet another example, a government realm may be provided fora government, and the like. For example, the government realm may becatered for a specific government and may have a heightened level ofsecurity than a commercial realm. For example, Oracle CloudInfrastructure (OCI) currently offers a realm for commercial regions andtwo realms (e.g., FedRAMP authorized and IL5 authorized) for governmentcloud regions.

In certain embodiments, an AD can be subdivided into one or more faultdomains. A fault domain is a grouping of infrastructure resources withinan AD to provide anti-affinity. Fault domains allow for the distributionof compute instances such that the instances are not on the samephysical hardware within a single AD. This is known as anti-affinity. Afault domain refers to a set of hardware components (computers,switches, and more) that share a single point of failure. A compute poolis logically divided up into fault domains. Due to this, a hardwarefailure or compute hardware maintenance event that affects one faultdomain does not affect instances in other fault domains. Depending onthe embodiment, the number of fault domains for each AD may vary. Forinstance, in certain embodiments each AD contains three fault domains. Afault domain acts as a logical data center within an AD.

When a customer subscribes to an IaaS service, resources from CSPI areprovisioned for the customer and associated with the customer's tenancy.The customer can use these provisioned resources to build privatenetworks and deploy resources on these networks. The customer networksthat are hosted in the cloud by the CSPI are referred to as virtualcloud networks (VCNs). A customer can set up one or more virtual cloudnetworks (VCNs) using CSPI resources allocated for the customer. A VCNis a virtual or software defined private network. The customer resourcesthat are deployed in the customer's VCN can include compute instances(e.g., virtual machines, bare-metal instances) and other resources.These compute instances may represent various customer workloads such asapplications, load balancers, databases, and the like. A computeinstance deployed on a VCN can communicate with public accessibleendpoints (“public endpoints”) over a public network such as theInternet, with other instances in the same VCN or other VCNs (e.g., thecustomer's other VCNs, or VCNs not belonging to the customer), with thecustomer's on-premise data centers or networks, and with serviceendpoints, and other types of endpoints.

The CSP may provide various services using the CSPI. In some instances,customers of CSPI may themselves act like service providers and provideservices using CSPI resources. A service provider may expose a serviceendpoint, which is characterized by identification information (e.g., anIP Address, a DNS name and port). A customer's resource (e.g., a computeinstance) can consume a particular service by accessing a serviceendpoint exposed by the service for that particular service. Theseservice endpoints are generally endpoints that are publicly accessibleby users using public IP addresses associated with the endpoints via apublic communication network such as the Internet. Network endpointsthat are publicly accessible are also sometimes referred to as publicendpoints.

In certain embodiments, a service provider may expose a service via anendpoint (sometimes referred to as a service endpoint) for the service.Customers of the service can then use this service endpoint to accessthe service. In certain implementations, a service endpoint provided fora service can be accessed by multiple customers that intend to consumethat service. In other implementations, a dedicated service endpoint maybe provided for a customer such that only that customer can access theservice using that dedicated service endpoint.

In certain embodiments, when a VCN is created, it is associated with aprivate overlay Classless Inter-Domain Routing (CIDR) address space,which is a range of private overlay IP addresses that are assigned tothe VCN (e.g., 10.0/16). A VCN includes associated subnets, routetables, and gateways. A VCN resides within a single region but can spanone or more or all of the region's availability domains. A gateway is avirtual interface that is configured for a VCN and enables communicationof traffic to and from the VCN to one or more endpoints outside the VCN.One or more different types of gateways may be configured for a VCN toenable communication to and from different types of endpoints.

A VCN can be subdivided into one or more sub-networks such as one ormore subnets. A subnet is thus a unit of configuration or a subdivisionthat can be created within a VCN. A VCN can have one or multiplesubnets. Each subnet within a VCN is associated with a contiguous rangeof overlay IP addresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do notoverlap with other subnets in that VCN and which represent an addressspace subset within the address space of the VCN.

Each compute instance is associated with a virtual network interfacecard (VNIC), that enables the compute instance to participate in asubnet of a VCN. A VNIC is a logical representation of physical NetworkInterface Card (NIC). In general. a VNIC is an interface between anentity (e.g., a compute instance, a service) and a virtual network. AVNIC exists in a subnet, has one or more associated IP addresses, andassociated security rules or policies. A VNIC is equivalent to a Layer-2port on a switch. A VNIC is attached to a compute instance and to asubnet within a VCN. A VNIC associated with a compute instance enablesthe compute instance to be a part of a subnet of a VCN and enables thecompute instance to communicate (e.g., send and receive packets) withendpoints that are on the same subnet as the compute instance, withendpoints in different subnets in the VCN, or with endpoints outside theVCN. The VNIC associated with a compute instance thus determines how thecompute instance connects with endpoints inside and outside the VCN. AVNIC for a compute instance is created and associated with that computeinstance when the compute instance is created and added to a subnetwithin a VCN. For a subnet comprising a set of compute instances, thesubnet contains the VNICs corresponding to the set of compute instances,each VNIC attached to a compute instance within the set of computerinstances.

Each compute instance is assigned a private overlay IP address via theVNIC associated with the compute instance. This private overlay IPaddress is assigned to the VNIC that is associated with the computeinstance when the compute instance is created and used for routingtraffic to and from the compute instance. All VNICs in a given subnetuse the same route table, security lists, and DHCP options. As describedabove, each subnet within a VCN is associated with a contiguous range ofoverlay IP addresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do notoverlap with other subnets in that VCN and which represent an addressspace subset within the address space of the VCN. For a VNIC on aparticular subnet of a VCN, the private overlay IP address that isassigned to the VNIC is an address from the contiguous range of overlayIP addresses allocated for the subnet.

In certain embodiments, a compute instance may optionally be assignedadditional overlay IP addresses in addition to the private overlay IPaddress, such as, for example, one or more public IP addresses if in apublic subnet. These multiple addresses are assigned either on the sameVNIC or over multiple VNICs that are associated with the computeinstance. Each instance however has a primary VNIC that is createdduring instance launch and is associated with the overlay private IPaddress assigned to the instance—this primary VNIC cannot be removed.Additional VNICs, referred to as secondary VNICs, can be added to anexisting instance in the same availability domain as the primary VNIC.All the VNICs are in the same availability domain as the instance. Asecondary VNIC can be in a subnet in the same VCN as the primary VNIC,or in a different subnet that is either in the same VCN or a differentone.

A compute instance may optionally be assigned a public IP address if itis in a public subnet. A subnet can be designated as either a publicsubnet or a private subnet at the time the subnet is created. A privatesubnet means that the resources (e.g., compute instances) and associatedVNICs in the subnet cannot have public overlay IP addresses. A publicsubnet means that the resources and associated VNICs in the subnet canhave public IP addresses. A customer can designate a subnet to existeither in a single availability domain or across multiple availabilitydomains in a region or realm.

As described above, a VCN may be subdivided into one or more subnets. Incertain embodiments, a Virtual Router (VR) configured for the VCN(referred to as the VCN VR or just VR) enables communications betweenthe subnets of the VCN. For a subnet within a VCN, the VR represents alogical gateway for that subnet that enables the subnet (i.e., thecompute instances on that subnet) to communicate with endpoints on othersubnets within the VCN, and with other endpoints outside the VCN. TheVCN VR is a logical entity that is configured to route traffic betweenVNICs in the VCN and virtual gateways (“gateways”) associated with theVCN. Gateways are further described below with respect to FIG. 1 . A VCNVR is a Layer-3/IP Layer concept. In one embodiment, there is one VCN VRfor a VCN where the VCN VR has potentially an unlimited number of portsaddressed by IP addresses, with one port for each subnet of the VCN. Inthis manner, the VCN VR has a different IP address for each subnet inthe VCN that the VCN VR is attached to. The VR is also connected to thevarious gateways configured for a VCN. In certain embodiments, aparticular overlay IP address from the overlay IP address range for asubnet is reserved for a port of the VCN VR for that subnet. Forexample, consider a VCN having two subnets with associated addressranges 10.0/16 and 10.1/16, respectively. For the first subnet withinthe VCN with address range 10.0/16, an address from this range isreserved for a port of the VCN VR for that subnet. In some instances,the first IP address from the range may be reserved for the VCN VR. Forexample, for the subnet with overlay IP address range 10.0/16, IPaddress 10.0.0.1 may be reserved for a port of the VCN VR for thatsubnet. For the second subnet within the same VCN with address range10.1/16, the VCN VR may have a port for that second subnet with IPaddress 10.1.0.1. The VCN VR has a different IP address for each of thesubnets in the VCN.

In some other embodiments, each subnet within a VCN may have its ownassociated VR that is addressable by the subnet using a reserved ordefault IP address associated with the VR. The reserved or default IPaddress may, for example, be the first IP address from the range of IPaddresses associated with that subnet. The VNICs in the subnet cancommunicate (e.g., send and receive packets) with the VR associated withthe subnet using this default or reserved IP address. In such anembodiment, the VR is the ingress/egress point for that subnet. The VRassociated with a subnet within the VCN can communicate with other VRsassociated with other subnets within the VCN. The VRs can alsocommunicate with gateways associated with the VCN. The VR function for asubnet is running on or executed by one or more NVDs executing VNICsfunctionality for VNICs in the subnet.

Route tables, security rules, and DHCP options may be configured for aVCN. Route tables are virtual route tables for the VCN and include rulesto route traffic from subnets within the VCN to destinations outside theVCN by way of gateways or specially configured instances. A VCN's routetables can be customized to control how packets are forwarded/routed toand from the VCN. DHCP options refers to configuration information thatis automatically provided to the instances when they boot up.

Security rules configured for a VCN represent overlay firewall rules forthe VCN. The security rules can include ingress and egress rules, andspecify the types of traffic (e.g., based upon protocol and port) thatis allowed in and out of the instances within the VCN. The customer canchoose whether a given rule is stateful or stateless. For instance, thecustomer can allow incoming SSH traffic from anywhere to a set ofinstances by setting up a stateful ingress rule with source CIDR0.0.0.0/0, and destination TCP port 22. Security rules can beimplemented using network security groups or security lists. A networksecurity group consists of a set of security rules that apply only tothe resources in that group. A security list, on the other hand,includes rules that apply to all the resources in any subnet that usesthe security list. A VCN may be provided with a default security listwith default security rules. DHCP options configured for a VCN provideconfiguration information that is automatically provided to theinstances in the VCN when the instances boot up.

In certain embodiments, the configuration information for a VCN isdetermined and stored by a VCN Control Plane. The configurationinformation for a VCN may include, for example, information about: theaddress range associated with the VCN, subnets within the VCN andassociated information, one or more VRs associated with the VCN, computeinstances in the VCN and associated VNICs, NVDs executing the variousvirtualization network functions (e.g., VNICs, VRs, gateways) associatedwith the VCN, state information for the VCN, and other VCN-relatedinformation. In certain embodiments, a VCN Distribution Servicepublishes the configuration information stored by the VCN Control Plane,or portions thereof, to the NVDs. The distributed information may beused to update information (e.g., forwarding tables, routing tables,etc.) stored and used by the NVDs to forward packets to and from thecompute instances in the VCN.

In certain embodiments, the creation of VCNs and subnets are handled bya VCN Control Plane (CP) and the launching of compute instances ishandled by a Compute Control Plane. The Compute Control Plane isresponsible for allocating the physical resources for the computeinstance and then calls the VCN Control Plane to create and attach VNICsto the compute instance. The VCN CP also sends VCN data mappings to theVCN data plane that is configured to perform packet forwarding androuting functions. In certain embodiments, the VCN CP provides adistribution service that is responsible for providing updates to theVCN data plane. Examples of a VCN Control Plane are also depicted inFIGS. 17, 18, 19, and 20 (see references 1716, 1816, 1916, and 2016) anddescribed below.

A customer may create one or more VCNs using resources hosted by CSPI. Acompute instance deployed on a customer VCN may communicate withdifferent endpoints. These endpoints can include endpoints that arehosted by CSPI and endpoints outside CSPI.

Various different architectures for implementing cloud-based serviceusing CSPI are depicted in FIGS. 1, 2, 3, 4, 5, 17, 18, 19, and 21 , andare described below. FIG. 1 is a high level diagram of a distributedenvironment 100 showing an overlay or customer VCN hosted by CSPIaccording to certain embodiments. The distributed environment depictedin FIG. 1 includes multiple components in the overlay network.Distributed environment 100 depicted in FIG. 1 is merely an example andis not intended to unduly limit the scope of claimed embodiments. Manyvariations, alternatives, and modifications are possible. For example,in some implementations, the distributed environment depicted in FIG. 1may have more or fewer systems or components than those shown in FIG. 1, may combine two or more systems, or may have a different configurationor arrangement of systems.

As shown in the example depicted in FIG. 1 , distributed environment 100comprises CSPI 101 that provides services and resources that customerscan subscribe to and use to build their virtual cloud networks (VCNs).In certain embodiments, CSPI 101 offers IaaS services to subscribingcustomers. The data centers within CSPI 101 may be organized into one ormore regions. One example region “Region US” 102 is shown in FIG. 1 . Acustomer has configured a customer VCN 104 for region 102. The customermay deploy various compute instances on VCN 104, where the computeinstances may include virtual machines or bare metal instances.

Examples of instances include applications, database, load balancers,and the like.

In the embodiment depicted in FIG. 1 , customer VCN 104 comprises twosubnets, namely, “Subnet-1” and “Subnet-2”, each subnet with its ownCIDR IP address range. In FIG. 1 , the overlay IP address range forSubnet-1 is 10.0/16 and the address range for Subnet-2 is 10.1/16. A VCNVirtual Router 105 represents a logical gateway for the VCN that enablescommunications between subnets of the VCN 104, and with other endpointsoutside the VCN. VCN VR 105 is configured to route traffic between VNICsin VCN 104 and gateways associated with VCN 104. VCN VR 105 provides aport for each subnet of VCN 104. For example, VR 105 may provide a portwith IP address 10.0.0.1 for Subnet-1 and a port with IP address10.1.0.1 for Subnet-2.

Multiple compute instances may be deployed on each subnet, where thecompute instances can be virtual machine instances, and/or bare metalinstances. The compute instances in a subnet may be hosted by one ormore host machines within CSPI 101. A compute instance participates in asubnet via a VNIC associated with the compute instance. For example, asshown in FIG. 1 , a compute instance C1 is part of Subnet-1 via a VNICassociated with the compute instance. Likewise, compute instance C2 ispart of Subnet-1 via a VNIC associated with C2. In a similar manner,multiple compute instances, which may be virtual machine instances orbare metal instances, may be part of Subnet-1. Via its associated VNIC,each compute instance is assigned a private overlay IP address and a MACaddress. For example, in FIG. 1 , compute instance C1 has an overlay IPaddress of 10.0.0.2 and a MAC address of M1, while compute instance C2has an private overlay IP address of 10.0.0.3 and a MAC address of M2.Each compute instance in Subnet-1, including compute instances C1 andC2, has a default route to VCN VR 105 using IP address 10.0.0.1, whichis the IP address for a port of VCN VR 105 for Subnet-1.

Subnet-2 can have multiple compute instances deployed on it, includingvirtual machine instances and/or bare metal instances. For example, asshown in FIG. 1 , compute instances D1 and D2 are part of Subnet-2 viaVNICs associated with the respective compute instances. In theembodiment depicted in FIG. 1 , compute instance D1 has an overlay IPaddress of 10.1.0.2 and a MAC address of MM1, while compute instance D2has an private overlay IP address of 10.1.0.3 and a MAC address of MM2.Each compute instance in Subnet-2, including compute instances D1 andD2, has a default route to VCN VR 105 using IP address 10.1.0.1, whichis the IP address for a port of VCN VR 105 for Subnet-2.

VCN A 104 may also include one or more load balancers. For example, aload balancer may be provided for a subnet and may be configured to loadbalance traffic across multiple compute instances on the subnet. A loadbalancer may also be provided to load balance traffic across subnets inthe VCN.

A particular compute instance deployed on VCN 104 can communicate withvarious different endpoints. These endpoints may include endpoints thatare hosted by CSPI 200 and endpoints outside CSPI 200. Endpoints thatare hosted by CSPI 101 may include: an endpoint on the same subnet asthe particular compute instance (e.g., communications between twocompute instances in Subnet-1); an endpoint on a different subnet butwithin the same VCN (e.g., communication between a compute instance inSubnet-1 and a compute instance in Subnet-2); an endpoint in a differentVCN in the same region (e.g., communications between a compute instancein Subnet-1 and an endpoint in a VCN in the same region 106 or 110,communications between a compute instance in Subnet-1 and an endpoint inservice network 110 in the same region); or an endpoint in a VCN in adifferent region (e.g., communications between a compute instance inSubnet-1 and an endpoint in a VCN in a different region 108). A computeinstance in a subnet hosted by CSPI 101 may also communicate withendpoints that are not hosted by CSPI 101 (i.e., are outside CSPI 101).These outside endpoints include endpoints in the customer's on-premisenetwork 116, endpoints within other remote cloud hosted networks 118,public endpoints 114 accessible via a public network such as theInternet, and other endpoints.

Communications between compute instances on the same subnet arefacilitated using VNICs associated with the source compute instance andthe destination compute instance. For example, compute instance C1 inSubnet-1 may want to send packets to compute instance C2 in Subnet-1.For a packet originating at a source compute instance and whosedestination is another compute instance in the same subnet, the packetis first processed by the VNIC associated with the source computeinstance. Processing performed by the VNIC associated with the sourcecompute instance can include determining destination information for thepacket from the packet headers, identifying any policies (e.g., securitylists) configured for the VNIC associated with the source computeinstance, determining a next hop for the packet, performing any packetencapsulation/decapsulation functions as needed, and thenforwarding/routing the packet to the next hop with the goal offacilitating communication of the packet to its intended destination.When the destination compute instance is in the same subnet as thesource compute instance, the VNIC associated with the source computeinstance is configured to identify the VNIC associated with thedestination compute instance and forward the packet to that VNIC forprocessing. The VNIC associated with the destination compute instance isthen executed and forwards the packet to the destination computeinstance.

For a packet to be communicated from a compute instance in a subnet toan endpoint in a different subnet in the same VCN, the communication isfacilitated by the VNICs associated with the source and destinationcompute instances and the VCN VR. For example, if compute instance C1 inSubnet-1 in FIG. 1 wants to send a packet to compute instance D1 inSubnet-2, the packet is first processed by the VNIC associated withcompute instance C1. The VNIC associated with compute instance C1 isconfigured to route the packet to the VCN VR 105 using default route orport 10.0.0.1 of the VCN VR. VCN VR 105 is configured to route thepacket to Subnet-2 using port 10.1.0.1. The packet is then received andprocessed by the VNIC associated with D1 and the VNIC forwards thepacket to compute instance D1.

For a packet to be communicated from a compute instance in VCN 104 to anendpoint that is outside VCN 104, the communication is facilitated bythe VNIC associated with the source compute instance, VCN VR 105, andgateways associated with VCN 104. One or more types of gateways may beassociated with VCN 104. A gateway is an interface between a VCN andanother endpoint, where the another endpoint is outside the VCN. Agateway is a Layer-3/IP layer concept and enables a VCN to communicatewith endpoints outside the VCN. A gateway thus facilitates traffic flowbetween a VCN and other VCNs or networks. Various different types ofgateways may be configured for a VCN to facilitate different types ofcommunications with different types of endpoints. Depending upon thegateway, the communications may be over public networks (e.g., theInternet) or over private networks. Various communication protocols maybe used for these communications.

For example, compute instance C1 may want to communicate with anendpoint outside VCN 104. The packet may be first processed by the VNICassociated with source compute instance C1. The VNIC processingdetermines that the destination for the packet is outside the Subnet-1of C1. The VNIC associated with C1 may forward the packet to VCN VR 105for VCN 104. VCN VR 105 then processes the packet and as part of theprocessing, based upon the destination for the packet, determines aparticular gateway associated with VCN 104 as the next hop for thepacket. VCN VR 105 may then forward the packet to the particularidentified gateway. For example, if the destination is an endpointwithin the customer's on-premise network, then the packet may beforwarded by VCN VR 105 to Dynamic Routing Gateway (DRG) gateway 122configured for VCN 104. The packet may then be forwarded from thegateway to a next hop to facilitate communication of the packet to itfinal intended destination.

Various different types of gateways may be configured for a VCN.Examples of gateways that may be configured for a VCN are depicted inFIG. 1 and described below. Examples of gateways associated with a VCNare also depicted in FIGS. 17, 18, 19, and 20 (for example, gatewaysreferenced by reference numbers 1734, 1736, 1738, 1834, 1836, 1838,1934, 1936, 1938, 2034, 2036, and 2038) and described below. As shown inthe embodiment depicted in FIG. 1 , a Dynamic Routing Gateway (DRG) 122may be added to or be associated with customer VCN 104 and provides apath for private network traffic communication between customer VCN 104and another endpoint, where the another endpoint can be the customer'son-premise network 116, a VCN 108 in a different region of CSPI 101, orother remote cloud networks 118 not hosted by CSPI 101. Customeron-premise network 116 may be a customer network or a customer datacenter built using the customer's resources. Access to customeron-premise network 116 is generally very restricted. For a customer thathas both a customer on-premise network 116 and one or more VCNs 104deployed or hosted in the cloud by CSPI 101, the customer may want theiron-premise network 116 and their cloud-based VCN 104 to be able tocommunicate with each other. This enables a customer to build anextended hybrid environment encompassing the customer's VCN 104 hostedby CSPI 101 and their on-premises network 116. DRG 122 enables thiscommunication. To enable such communications, a communication channel124 is set up where one endpoint of the channel is in customeron-premise network 116 and the other endpoint is in CSPI 101 andconnected to customer VCN 104. Communication channel 124 can be overpublic communication networks such as the Internet or privatecommunication networks. Various different communication protocols may beused such as IPsec VPN technology over a public communication networksuch as the Internet, Oracle's FastConnect technology that uses aprivate network instead of a public network, and others. The device orequipment in customer on-premise network 116 that forms one end pointfor communication channel 124 is referred to as the customer premiseequipment (CPE), such as CPE 126 depicted in FIG. 1 . On the CSPI 101side, the endpoint may be a host machine executing DRG 122.

In certain embodiments, a Remote Peering Connection (RPC) can be addedto a DRG, which allows a customer to peer one VCN with another VCN in adifferent region. Using such an RPC, customer VCN 104 can use DRG 122 toconnect with a VCN 108 in another region. DRG 122 may also be used tocommunicate with other remote cloud networks 118, not hosted by CSPI 101such as a Microsoft Azure cloud, Amazon AWS cloud, and others.

As shown in FIG. 1 , an Internet Gateway (IGW) 120 may be configured forcustomer VCN 104 the enables a compute instance on VCN 104 tocommunicate with public endpoints 114 accessible over a public networksuch as the Internet. IGW 1120 is a gateway that connects a VCN to apublic network such as the Internet. IGW 120 enables a public subnet(where the resources in the public subnet have public overlay IPaddresses) within a VCN, such as VCN 104, direct access to publicendpoints 112 on a public network 114 such as the Internet. Using IGW120, connections can be initiated from a subnet within VCN 104 or fromthe Internet.

A Network Address Translation (NAT) gateway 128 can be configured forcustomer's VCN 104 and enables cloud resources in the customer's VCN,which do not have dedicated public overlay IP addresses, access to theInternet and it does so without exposing those resources to directincoming Internet connections (e.g., L4-L7 connections). This enables aprivate subnet within a VCN, such as private Subnet-1 in VCN 104, withprivate access to public endpoints on the Internet. In NAT gateways,connections can be initiated only from the private subnet to the publicInternet and not from the Internet to the private subnet.

In certain embodiments, a Service Gateway (SGW) 126 can be configuredfor customer VCN 104 and provides a path for private network trafficbetween VCN 104 and supported services endpoints in a service network110. In certain embodiments, service network 110 may be provided by theCSP and may provide various services. An example of such a servicenetwork is Oracle's Services Network, which provides various servicesthat can be used by customers. For example, a compute instance (e.g., adatabase system) in a private subnet of customer VCN 104 can back updata to a service endpoint (e.g., Object Storage) without needing publicIP addresses or access to the Internet. In certain embodiments, a VCNcan have only one SGW, and connections can only be initiated from asubnet within the VCN and not from service network 110. If a VCN ispeered with another, resources in the other VCN typically cannot accessthe SGW. Resources in on-premises networks that are connected to a VCNwith FastConnect or VPN Connect can also use the service gatewayconfigured for that VCN.

In certain implementations, SGW 126 uses the concept of a serviceClassless Inter-Domain Routing (CIDR) label, which is a string thatrepresents all the regional public IP address ranges for the service orgroup of services of interest. The customer uses the service CIDR labelwhen they configure the SGW and related route rules to control trafficto the service. The customer can optionally utilize it when configuringsecurity rules without needing to adjust them if the service's public IPaddresses change in the future.

A Local Peering Gateway (LPG) 132 is a gateway that can be added tocustomer VCN 104 and enables VCN 104 to peer with another VCN in thesame region. Peering means that the VCNs communicate using private IPaddresses, without the traffic traversing a public network such as theInternet or without routing the traffic through the customer'son-premises network 116. In preferred embodiments, a VCN has a separateLPG for each peering it establishes. Local Peering or VCN Peering is acommon practice used to establish network connectivity between differentapplications or infrastructure management functions.

Service providers, such as providers of services in service network 110,may provide access to services using different access models. Accordingto a public access model, services may be exposed as public endpointsthat are publicly accessible by compute instance in a customer VCN via apublic network such as the Internet and or may be privately accessiblevia SGW 126. According to a specific private access model, services aremade accessible as private IP endpoints in a private subnet in thecustomer's VCN. This is referred to as a Private Endpoint (PE) accessand enables a service provider to expose their service as an instance inthe customer's private network. A Private Endpoint resource represents aservice within the customer's VCN. Each PE manifests as a VNIC (referredto as a PE-VNIC, with one or more private IPs) in a subnet chosen by thecustomer in the customer's VCN. A PE thus provides a way to present aservice within a private customer VCN subnet using a VNIC. Since theendpoint is exposed as a VNIC, all the features associates with a VNICsuch as routing rules, security lists, etc., are now available for thePE VNIC.

A service provider can register their service to enable access through aPE. The provider can associate policies with the service that restrictsthe service's visibility to the customer tenancies. A provider canregister multiple services under a single virtual IP address (VIP),especially for multi-tenant services. There may be multiple such privateendpoints (in multiple VCNs) that represent the same service.

Compute instances in the private subnet can then use the PE VNIC'sprivate IP address or the service DNS name to access the service.Compute instances in the customer VCN can access the service by sendingtraffic to the private IP address of the PE in the customer VCN. APrivate Access Gateway (PAGW) 130 is a gateway resource that can beattached to a service provider VCN (e.g., a VCN in service network 110)that acts as an ingress/egress point for all traffic from/to customersubnet private endpoints. PAGW 130 enables a provider to scale thenumber of PE connections without utilizing its internal IP addressresources. A provider needs only configure one PAGW for any number ofservices registered in a single VCN. Providers can represent a serviceas a private endpoint in multiple VCNs of one or more customers. Fromthe customer's perspective, the PE VNIC, which, instead of beingattached to a customer's instance, appears attached to the service withwhich the customer wishes to interact. The traffic destined to theprivate endpoint is routed via PAGW 130 to the service. These arereferred to as customer-to-service private connections (C2Sconnections).

The PE concept can also be used to extend the private access for theservice to customer's on-premises networks and data centers, by allowingthe traffic to flow through FastConnect/IPsec links and the privateendpoint in the customer VCN. Private access for the service can also beextended to the customer's peered VCNs, by allowing the traffic to flowbetween LPG 132 and the PE in the customer's VCN.

A customer can control routing in a VCN at the subnet level, so thecustomer can specify which subnets in the customer's VCN, such as VCN104, use each gateway. A VCN's route tables are used to decide iftraffic is allowed out of a VCN through a particular gateway. Forexample, in a particular instance, a route table for a public subnetwithin customer VCN 104 may send non-local traffic through IGW 120. Theroute table for a private subnet within the same customer VCN 104 maysend traffic destined for CSP services through SGW 126. All remainingtraffic may be sent via the NAT gateway 128. Route tables only controltraffic going out of a VCN.

Security lists associated with a VCN are used to control traffic thatcomes into a VCN via a gateway via inbound connections. All resources ina subnet use the same route table and security lists. Security lists maybe used to control specific types of traffic allowed in and out ofinstances in a subnet of a VCN. Security list rules may comprise ingress(inbound) and egress (outbound) rules. For example, an ingress rule mayspecify an allowed source address range, while an egress rule mayspecify an allowed destination address range. Security rules may specifya particular protocol (e.g., TCP, ICMP), a particular port (e.g., 22 forSSH, 3389 for Windows RDP), etc. In certain implementations, aninstance's operating system may enforce its own firewall rules that arealigned with the security list rules. Rules may be stateful (e.g., aconnection is tracked and the response is automatically allowed withoutan explicit security list rule for the response traffic) or stateless.

Access from a customer VCN (i.e., by a resource or compute instancedeployed on VCN 104) can be categorized as public access, privateaccess, or dedicated access. Public access refers to an access modelwhere a public IP address or a NAT is used to access a public endpoint.Private access enables customer workloads in VCN 104 with private IPaddresses (e.g., resources in a private subnet) to access serviceswithout traversing a public network such as the Internet. In certainembodiments, CSPI 101 enables customer VCN workloads with private IPaddresses to access the (public service endpoints of) services using aservice gateway. A service gateway thus offers a private access model byestablishing a virtual link between the customer's VCN and the service'spublic endpoint residing outside the customer's private network.

Additionally, CSPI may offer dedicated public access using technologiessuch as FastConnect public peering where customer on-premises instancescan access one or more services in a customer VCN using a FastConnectconnection and without traversing a public network such as the Internet.CSPI also may also offer dedicated private access using FastConnectprivate peering where customer on-premises instances with private IPaddresses can access the customer's VCN workloads using a FastConnectconnection. FastConnect is a network connectivity alternative to usingthe public Internet to connect a customer's on-premise network to CSPIand its services. FastConnect provides an easy, elastic, and economicalway to create a dedicated and private connection with higher bandwidthoptions and a more reliable and consistent networking experience whencompared to Internet-based connections.

FIG. 1 and the accompanying description above describes variousvirtualized components in an example virtual network. As describedabove, the virtual network is built on the underlying physical orsubstrate network. FIG. 2 depicts a simplified architectural diagram ofthe physical components in the physical network within CSPI 200 thatprovide the underlay for the virtual network according to certainembodiments. As shown, CSPI 200 provides a distributed environmentcomprising components and resources (e.g., compute, memory, andnetworking resources) provided by a cloud service provider (CSP). Thesecomponents and resources are used to provide cloud services (e.g., IaaSservices) to subscribing customers, i.e., customers that have subscribedto one or more services provided by the CSP. Based upon the servicessubscribed to by a customer, a subset of resources (e.g., compute,memory, and networking resources) of CSPI 200 are provisioned for thecustomer. Customers can then build their own cloud-based (i.e.,CSPI-hosted) customizable and private virtual networks using physicalcompute, memory, and networking resources provided by CSPI 200. Aspreviously indicated, these customer networks are referred to as virtualcloud networks (VCNs). A customer can deploy one or more customerresources, such as compute instances, on these customer VCNs. Computeinstances can be in the form of virtual machines, bare metal instances,and the like. CSPI 200 provides infrastructure and a set ofcomplementary cloud services that enable customers to build and run awide range of applications and services in a highly available hostedenvironment.

In the example embodiment depicted in FIG. 2 , the physical componentsof CSPI 200 include one or more physical host machines or physicalservers (e.g., 202, 206, 208), network virtualization devices (NVDs)(e.g., 210, 212), top-of-rack (TOR) switches (e.g., 214, 216), and aphysical network (e.g., 218), and switches in physical network 218. Thephysical host machines or servers may host and execute various computeinstances that participate in one or more subnets of a VCN. The computeinstances may include virtual machine instances, and bare metalinstances. For example, the various compute instances depicted in FIG. 1may be hosted by the physical host machines depicted in FIG. 2 . Thevirtual machine compute instances in a VCN may be executed by one hostmachine or by multiple different host machines. The physical hostmachines may also host virtual host machines, container-based hosts orfunctions, and the like. The VNICs and VCN VR depicted in FIG. 1 may beexecuted by the NVDs depicted in FIG. 2 . The gateways depicted in FIG.1 may be executed by the host machines and/or by the NVDs depicted inFIG. 2 .

The host machines or servers may execute a hypervisor (also referred toas a virtual machine monitor or VMM) that creates and enables avirtualized environment on the host machines. The virtualization orvirtualized environment facilitates cloud-based computing. One or morecompute instances may be created, executed, and managed on a hostmachine by a hypervisor on that host machine. The hypervisor on a hostmachine enables the physical computing resources of the host machine(e.g., compute, memory, and networking resources) to be shared betweenthe various compute instances executed by the host machine.

For example, as depicted in FIG. 2 , host machines 202 and 208 executehypervisors 260 and 266, respectively. These hypervisors may beimplemented using software, firmware, or hardware, or combinationsthereof. Typically, a hypervisor is a process or a software layer thatsits on top of the host machine's operating system (OS), which in turnexecutes on the hardware processors of the host machine. The hypervisorprovides a virtualized environment by enabling the physical computingresources (e.g., processing resources such as processors/cores, memoryresources, networking resources) of the host machine to be shared amongthe various virtual machine compute instances executed by the hostmachine. For example, in FIG. 2 , hypervisor 260 may sit on top of theOS of host machine 202 and enables the computing resources (e.g.,processing, memory, and networking resources) of host machine 202 to beshared between compute instances (e.g., virtual machines) executed byhost machine 202. A virtual machine can have its own operating system(referred to as a guest operating system), which may be the same as ordifferent from the OS of the host machine. The operating system of avirtual machine executed by a host machine may be the same as ordifferent from the operating system of another virtual machine executedby the same host machine. A hypervisor thus enables multiple operatingsystems to be executed alongside each other while sharing the samecomputing resources of the host machine. The host machines depicted inFIG. 2 may have the same or different types of hypervisors.

A compute instance can be a virtual machine instance or a bare metalinstance. In FIG. 2 , compute instances 268 on host machine 202 and 274on host machine 208 are examples of virtual machine instances. Hostmachine 206 is an example of a bare metal instance that is provided to acustomer.

In certain instances, an entire host machine may be provisioned to asingle customer, and all of the one or more compute instances (eithervirtual machines or bare metal instance) hosted by that host machinebelong to that same customer. In other instances, a host machine may beshared between multiple customers (i.e., multiple tenants). In such amulti-tenancy scenario, a host machine may host virtual machine computeinstances belonging to different customers. These compute instances maybe members of different VCNs of different customers. In certainembodiments, a bare metal compute instance is hosted by a bare metalserver without a hypervisor. When a bare metal compute instance isprovisioned, a single customer or tenant maintains control of thephysical CPU, memory, and network interfaces of the host machine hostingthe bare metal instance and the host machine is not shared with othercustomers or tenants.

As previously described, each compute instance that is part of a VCN isassociated with a VNIC that enables the compute instance to become amember of a subnet of the VCN. The VNIC associated with a computeinstance facilitates the communication of packets or frames to and fromthe compute instance. A VNIC is associated with a compute instance whenthe compute instance is created. In certain embodiments, for a computeinstance executed by a host machine, the VNIC associated with thatcompute instance is executed by an NVD connected to the host machine.For example, in FIG. 2 , host machine 202 executes a virtual machinecompute instance 268 that is associated with VNIC 276, and VNIC 276 isexecuted by NVD 210 connected to host machine 202. As another example,bare metal instance 272 hosted by host machine 206 is associated withVNIC 280 that is executed by NVD 212 connected to host machine 206. Asyet another example, VNIC 284 is associated with compute instance 274executed by host machine 208, and VNIC 284 is executed by NVD 212connected to host machine 208.

For compute instances hosted by a host machine, an NVD connected to thathost machine also executes VCN VRs corresponding to VCNs of which thecompute instances are members. For example, in the embodiment depictedin FIG. 2 , NVD 210 executes VCN VR 277 corresponding to the VCN ofwhich compute instance 268 is a member. NVD 212 may also execute one ormore VCN VRs 283 corresponding to VCNs corresponding to the computeinstances hosted by host machines 206 and 208.

A host machine may include one or more network interface cards (NIC)that enable the host machine to be connected to other devices. A NIC ona host machine may provide one or more ports (or interfaces) that enablethe host machine to be communicatively connected to another device. Forexample, a host machine may be connected to an NVD using one or moreports (or interfaces) provided on the host machine and on the NVD. Ahost machine may also be connected to other devices such as another hostmachine.

For example, in FIG. 2 , host machine 202 is connected to NVD 210 usinglink 220 that extends between a port 234 provided by a NIC 232 of hostmachine 202 and between a port 236 of NVD 210. Host machine 206 isconnected to NVD 212 using link 224 that extends between a port 246provided by a NIC 244 of host machine 206 and between a port 248 of NVD212. Host machine 208 is connected to NVD 212 using link 226 thatextends between a port 252 provided by a NIC 250 of host machine 208 andbetween a port 254 of NVD 212.

The NVDs are in turn connected via communication links totop-of-the-rack (TOR) switches, which are connected to physical network218 (also referred to as the switch fabric). In certain embodiments, thelinks between a host machine and an NVD, and between an NVD and a TORswitch are Ethernet links. For example, in FIG. 2 , NVDs 210 and 212 areconnected to TOR switches 214 and 216, respectively, using links 228 and230. In certain embodiments, the links 220, 224, 226, 228, and 230 areEthernet links. The collection of host machines and NVDs that areconnected to a TOR is sometimes referred to as a rack.

Physical network 218 provides a communication fabric that enables TORswitches to communicate with each other. Physical network 218 can be amulti-tiered network. In certain implementations, physical network 218is a multi-tiered Clos network of switches, with TOR switches 214 and216 representing the leaf level nodes of the multi-tiered and multi-nodephysical switching network 218. Different Clos network configurationsare possible including but not limited to a 2-tier network, a 3-tiernetwork, a 4-tier network, a 5-tier network, and in general a “n”-tierednetwork. An example of a Clos network is depicted in FIG. 5 anddescribed below.

Various different connection configurations are possible between hostmachines and NVDs such as one-to-one configuration, many-to-oneconfiguration, one-to-many configuration, and others. In a one-to-oneconfiguration implementation, each host machine is connected to its ownseparate NVD. For example, in FIG. 2 , host machine 202 is connected toNVD 210 via NIC 232 of host machine 202. In a many-to-one configuration,multiple host machines are connected to one NVD. For example, in FIG. 2, host machines 206 and 208 are connected to the same NVD 212 via NICs244 and 250, respectively.

In a one-to-many configuration, one host machine is connected tomultiple NVDs. FIG. 3 shows an example within CSPI 300 where a hostmachine is connected to multiple NVDs. As shown in FIG. 3 , host machine302 comprises a network interface card (NIC) 304 that includes multipleports 306 and 308. Host machine 300 is connected to a first NVD 310 viaport 306 and link 320, and connected to a second NVD 312 via port 308and link 322. Ports 306 and 308 may be Ethernet ports and the links 320and 322 between host machine 302 and NVDs 310 and 312 may be Ethernetlinks. NVD 310 is in turn connected to a first TOR switch 314 and NVD312 is connected to a second TOR switch 316. The links between NVDs 310and 312, and TOR switches 314 and 316 may be Ethernet links. TORswitches 314 and 316 represent the Tier-0 switching devices inmulti-tiered physical network 318.

The arrangement depicted in FIG. 3 provides two separate physicalnetwork paths to and from physical switch network 318 to host machine302: a first path traversing TOR switch 314 to NVD 310 to host machine302, and a second path traversing TOR switch 316 to NVD 312 to hostmachine 302. The separate paths provide for enhanced availability(referred to as high availability) of host machine 302. If there areproblems in one of the paths (e.g., a link in one of the paths goesdown) or devices (e.g., a particular NVD is not functioning), then theother path may be used for communications to/from host machine 302.

In the configuration depicted in FIG. 3 , the host machine is connectedto two different NVDs using two different ports provided by a NIC of thehost machine. In other embodiments, a host machine may include multipleNICs that enable connectivity of the host machine to multiple NVDs.

Referring back to FIG. 2 , an NVD is a physical device or component thatperforms one or more network and/or storage virtualization functions. AnNVD may be any device with one or more processing units (e.g., CPUs,Network Processing Units (NPUs), FPGAs, packet processing pipelines,etc.), memory including cache, and ports. The various virtualizationfunctions may be performed by software/firmware executed by the one ormore processing units of the NVD.

An NVD may be implemented in various different forms. For example, incertain embodiments, an NVD is implemented as an interface card referredto as a smartNIC or an intelligent NIC with an embedded processoronboard. A smartNIC is a separate device from the NICs on the hostmachines. In FIG. 2 , the NVDs 210 and 212 may be implemented assmartNICs that are connected to host machines 202, and host machines 206and 208, respectively.

A smartNIC is however just one example of an NVD implementation. Variousother implementations are possible. For example, in some otherimplementations, an NVD or one or more functions performed by the NVDmay be incorporated into or performed by one or more host machines, oneor more TOR switches, and other components of CSPI 200. For example, anNVD may be embodied in a host machine where the functions performed byan NVD are performed by the host machine. As another example, an NVD maybe part of a TOR switch or a TOR switch may be configured to performfunctions performed by an NVD that enables the TOR switch to performvarious complex packet transformations that are used for a public cloud.A TOR that performs the functions of an NVD is sometimes referred to asa smart TOR. In yet other implementations, where virtual machines (VMs)instances, but not bare metal (BM) instances, are offered to customers,functions performed by an NVD may be implemented inside a hypervisor ofthe host machine. In some other implementations, some of the functionsof the NVD may be offloaded to a centralized service running on a fleetof host machines.

In certain embodiments, such as when implemented as a smartNIC as shownin FIG. 2 , an NVD may comprise multiple physical ports that enable itto be connected to one or more host machines and to one or more TORswitches. A port on an NVD can be classified as a host-facing port (alsoreferred to as a “south port”) or a network-facing or TOR-facing port(also referred to as a “north port”). A host-facing port of an NVD is aport that is used to connect the NVD to a host machine. Examples ofhost-facing ports in FIG. 2 include port 236 on NVD 210, and ports 248and 254 on NVD 212. A network-facing port of an NVD is a port that isused to connect the NVD to a TOR switch. Examples of network-facingports in FIG. 2 include port 256 on NVD 210, and port 258 on NVD 212. Asshown in FIG. 2 , NVD 210 is connected to TOR switch 214 using link 228that extends from port 256 of NVD 210 to the TOR switch 214. Likewise,NVD 212 is connected to TOR switch 216 using link 230 that extends fromport 258 of NVD 212 to the TOR switch 216.

An NVD receives packets and frames from a host machine (e.g., packetsand frames generated by a compute instance hosted by the host machine)via a host-facing port and, after performing the necessary packetprocessing, may forward the packets and frames to a TOR switch via anetwork-facing port of the NVD. An NVD may receive packets and framesfrom a TOR switch via a network-facing port of the NVD and, afterperforming the necessary packet processing, may forward the packets andframes to a host machine via a host-facing port of the NVD.

In certain embodiments, there may be multiple ports and associated linksbetween an NVD and a TOR switch. These ports and links may be aggregatedto form a link aggregator group of multiple ports or links (referred toas a LAG). Link aggregation allows multiple physical links between twoend-points (e.g., between an NVD and a TOR switch) to be treated as asingle logical link. All the physical links in a given LAG may operatein full-duplex mode at the same speed. LAGs help increase the bandwidthand reliability of the connection between two endpoints. If one of thephysical links in the LAG goes down, traffic is dynamically andtransparently reassigned to one of the other physical links in the LAG.The aggregated physical links deliver higher bandwidth than eachindividual link. The multiple ports associated with a LAG are treated asa single logical port. Traffic can be load-balanced across the multiplephysical links of a LAG. One or more LAGs may be configured between twoendpoints. The two endpoints may be between an NVD and a TOR switch,between a host machine and an NVD, and the like.

An NVD implements or performs network virtualization functions. Thesefunctions are performed by software/firmware executed by the NVD.Examples of network virtualization functions include without limitation:packet encapsulation and de-capsulation functions; functions forcreating a VCN network; functions for implementing network policies suchas VCN security list (firewall) functionality; functions that facilitatethe routing and forwarding of packets to and from compute instances in aVCN; and the like. In certain embodiments, upon receiving a packet, anNVD is configured to execute a packet processing pipeline for processingthe packet and determining how the packet is to be forwarded or routed.As part of this packet processing pipeline, the NVD may execute one ormore virtual functions associated with the overlay network such asexecuting VNICs associated with cis in the VCN, executing a VirtualRouter (VR) associated with the VCN, the encapsulation and decapsulationof packets to facilitate forwarding or routing in the virtual network,execution of certain gateways (e.g., the Local Peering Gateway), theimplementation of Security Lists, Network Security Groups, networkaddress translation (NAT) functionality (e.g., the translation of PublicIP to Private IP on a host by host basis), throttling functions, andother functions.

In certain embodiments, the packet processing data path in an NVD maycomprise multiple packet pipelines, each composed of a series of packettransformation stages. In certain implementations, upon receiving apacket, the packet is parsed and classified to a single pipeline. Thepacket is then processed in a linear fashion, one stage after another,until the packet is either dropped or sent out over an interface of theNVD. These stages provide basic functional packet processing buildingblocks (e.g., validating headers, enforcing throttle, inserting newLayer-2 headers, enforcing L4 firewall, VCN encapsulation/decapsulation,etc.) so that new pipelines can be constructed by composing existingstages, and new functionality can be added by creating new stages andinserting them into existing pipelines.

An NVD may perform both control plane and data plane functionscorresponding to a control plane and a data plane of a VCN. Examples ofa VCN Control Plane are also depicted in FIGS. 17, 18, 19, and 20 (seereferences 1716, 1816, 1916, and 2016) and described below. Examples ofa VCN Data Plane are depicted in FIGS. 17, 18, 19, and 20 (seereferences 1718, 1818, 1918, and 2018) and described below. The controlplane functions include functions used for configuring a network (e.g.,setting up routes and route tables, configuring VNICs, etc.) thatcontrols how data is to be forwarded. In certain embodiments, a VCNControl Plane is provided that computes all the overlay-to-substratemappings centrally and publishes them to the NVDs and to the virtualnetwork edge devices such as various gateways such as the DRG, the SGW,the IGW, etc. Firewall rules may also be published using the samemechanism. In certain embodiments, an NVD only gets the mappings thatare relevant for that NVD. The data plane functions include functionsfor the actual routing/forwarding of a packet based upon configurationset up using control plane. A VCN data plane is implemented byencapsulating the customer's network packets before they traverse thesubstrate network. The encapsulation/decapsulation functionality isimplemented on the NVDs. In certain embodiments, an NVD is configured tointercept all network packets in and out of host machines and performnetwork virtualization functions.

As indicated above, an NVD executes various virtualization functionsincluding VNICs and VCN VRs. An NVD may execute VNICs associated withthe compute instances hosted by one or more host machines connected tothe VNIC. For example, as depicted in FIG. 2 , NVD 210 executes thefunctionality for VNIC 276 that is associated with compute instance 268hosted by host machine 202 connected to NVD 210. As another example, NVD212 executes VNIC 280 that is associated with bare metal computeinstance 272 hosted by host machine 206, and executes VNIC 284 that isassociated with compute instance 274 hosted by host machine 208. A hostmachine may host compute instances belonging to different VCNs, whichbelong to different customers, and the NVD connected to the host machinemay execute the VNICs (i.e., execute VNICs-relate functionality)corresponding to the compute instances.

An NVD also executes VCN Virtual Routers corresponding to the VCNs ofthe compute instances. For example, in the embodiment depicted in FIG. 2, NVD 210 executes VCN VR 277 corresponding to the VCN to which computeinstance 268 belongs. NVD 212 executes one or more VCN VRs 283corresponding to one or more VCNs to which compute instances hosted byhost machines 206 and 208 belong. In certain embodiments, the VCN VRcorresponding to that VCN is executed by all the NVDs connected to hostmachines that host at least one compute instance belonging to that VCN.If a host machine hosts compute instances belonging to different VCNs,an NVD connected to that host machine may execute VCN VRs correspondingto those different VCNs.

In addition to VNICs and VCN VRs, an NVD may execute various software(e.g., daemons) and include one or more hardware components thatfacilitate the various network virtualization functions performed by theNVD. For purposes of simplicity, these various components are groupedtogether as “packet processing components” shown in FIG. 2 . Forexample, NVD 210 comprises packet processing components 286 and NVD 212comprises packet processing components 288. For example, the packetprocessing components for an NVD may include a packet processor that isconfigured to interact with the NVD's ports and hardware interfaces tomonitor all packets received by and communicated using the NVD and storenetwork information. The network information may, for example, includenetwork flow information identifying different network flows handled bythe NVD and per flow information (e.g., per flow statistics). In certainembodiments, network flows information may be stored on a per VNICbasis. The packet processor may perform packet-by-packet manipulationsas well as implement stateful NAT and L4 firewall (FW). As anotherexample, the packet processing components may include a replicationagent that is configured to replicate information stored by the NVD toone or more different replication target stores. As yet another example,the packet processing components may include a logging agent that isconfigured to perform logging functions for the NVD. The packetprocessing components may also include software for monitoring theperformance and health of the NVD and, also possibly of monitoring thestate and health of other components connected to the NVD.

FIG. 1 shows the components of an example virtual or overlay networkincluding a VCN, subnets within the VCN, compute instances deployed onsubnets, VNICs associated with the compute instances, a VR for a VCN,and a set of gateways configured for the VCN. The overlay componentsdepicted in FIG. 1 may be executed or hosted by one or more of thephysical components depicted in FIG. 2 . For example, the computeinstances in a VCN may be executed or hosted by one or more hostmachines depicted in FIG. 2 . For a compute instance hosted by a hostmachine, the VNIC associated with that compute instance is typicallyexecuted by an NVD connected to that host machine (i.e., the VNICfunctionality is provided by the NVD connected to that host machine).The VCN VR function for a VCN is executed by all the NVDs that areconnected to host machines hosting or executing the compute instancesthat are part of that VCN. The gateways associated with a VCN may beexecuted by one or more different types of NVDs. For example, certaingateways may be executed by smartNICs, while others may be executed byone or more host machines or other implementations of NVDs.

As described above, a compute instance in a customer VCN may communicatewith various different endpoints, where the endpoints can be within thesame subnet as the source compute instance, in a different subnet butwithin the same VCN as the source compute instance, or with an endpointthat is outside the VCN of the source compute instance. Thesecommunications are facilitated using VNICs associated with the computeinstances, the VCN VRs, and the gateways associated with the VCNs.

For communications between two compute instances on the same subnet in aVCN, the communication is facilitated using VNICs associated with thesource and destination compute instances. The source and destinationcompute instances may be hosted by the same host machine or by differenthost machines. A packet originating from a source compute instance maybe forwarded from a host machine hosting the source compute instance toan NVD connected to that host machine. On the NVD, the packet isprocessed using a packet processing pipeline, which can includeexecution of the VNIC associated with the source compute instance. Sincethe destination endpoint for the packet is within the same subnet,execution of the VNIC associated with the source compute instanceresults in the packet being forwarded to an NVD executing the VNICassociated with the destination compute instance, which then processesand forwards the packet to the destination compute instance. The VNICsassociated with the source and destination compute instances may beexecuted on the same NVD (e.g., when both the source and destinationcompute instances are hosted by the same host machine) or on differentNVDs (e.g., when the source and destination compute instances are hostedby different host machines connected to different NVDs). The VNICs mayuse routing/forwarding tables stored by the NVD to determine the nexthop for the packet.

For a packet to be communicated from a compute instance in a subnet toan endpoint in a different subnet in the same VCN, the packetoriginating from the source compute instance is communicated from thehost machine hosting the source compute instance to the NVD connected tothat host machine. On the NVD, the packet is processed using a packetprocessing pipeline, which can include execution of one or more VNICs,and the VR associated with the VCN. For example, as part of the packetprocessing pipeline, the NVD executes or invokes functionalitycorresponding to the VNIC (also referred to as executes the VNIC)associated with source compute instance. The functionality performed bythe VNIC may include looking at the VLAN tag on the packet. Since thepacket's destination is outside the subnet, the VCN VR functionality isnext invoked and executed by the NVD. The VCN VR then routes the packetto the NVD executing the VNIC associated with the destination computeinstance. The VNIC associated with the destination compute instance thenprocesses the packet and forwards the packet to the destination computeinstance. The VNICs associated with the source and destination computeinstances may be executed on the same NVD (e.g., when both the sourceand destination compute instances are hosted by the same host machine)or on different NVDs (e.g., when the source and destination computeinstances are hosted by different host machines connected to differentNVDs).

If the destination for the packet is outside the VCN of the sourcecompute instance, then the packet originating from the source computeinstance is communicated from the host machine hosting the sourcecompute instance to the NVD connected to that host machine. The NVDexecutes the VNIC associated with the source compute instance. Since thedestination end point of the packet is outside the VCN, the packet isthen processed by the VCN VR for that VCN. The NVD invokes the VCN VRfunctionality, which may result in the packet being forwarded to an NVDexecuting the appropriate gateway associated with the VCN. For example,if the destination is an endpoint within the customer's on-premisenetwork, then the packet may be forwarded by the VCN VR to the NVDexecuting the DRG gateway configured for the VCN. The VCN VR may beexecuted on the same NVD as the NVD executing the VNIC associated withthe source compute instance or by a different NVD. The gateway may beexecuted by an NVD, which may be a smartNIC, a host machine, or otherNVD implementation. The packet is then processed by the gateway andforwarded to a next hop that facilitates communication of the packet toits intended destination endpoint. For example, in the embodimentdepicted in FIG. 2 , a packet originating from compute instance 268 maybe communicated from host machine 202 to NVD 210 over link 220 (usingNIC 232). On NVD 210, VNIC 276 is invoked since it is the VNICassociated with source compute instance 268. VNIC 276 is configured toexamine the encapsulated information in the packet, and determine a nexthop for forwarding the packet with the goal of facilitatingcommunication of the packet to its intended destination endpoint, andthen forward the packet to the determined next hop.

A compute instance deployed on a VCN can communicate with variousdifferent endpoints. These endpoints may include endpoints that arehosted by CSPI 200 and endpoints outside CSPI 200. Endpoints hosted byCSPI 200 may include instances in the same VCN or other VCNs, which maybe the customer's VCNs, or VCNs not belonging to the customer.Communications between endpoints hosted by CSPI 200 may be performedover physical network 218. A compute instance may also communicate withendpoints that are not hosted by CSPI 200, or are outside CSPI 200.Examples of these endpoints include endpoints within a customer'son-premise network or data center, or public endpoints accessible over apublic network such as the Internet. Communications with endpointsoutside CSPI 200 may be performed over public networks (e.g., theInternet) (not shown in FIG. 2 ) or private networks (not shown in FIG.2 ) using various communication protocols.

The architecture of CSPI 200 depicted in FIG. 2 is merely an example andis not intended to be limiting. Variations, alternatives, andmodifications are possible in alternative embodiments. For example, insome implementations, CSPI 200 may have more or fewer systems orcomponents than those shown in FIG. 2 , may combine two or more systems,or may have a different configuration or arrangement of systems. Thesystems, subsystems, and other components depicted in FIG. 2 may beimplemented in software (e.g., code, instructions, program) executed byone or more processing units (e.g., processors, cores) of the respectivesystems, using hardware, or combinations thereof. The software may bestored on a non-transitory storage medium (e.g., on a memory device).

FIG. 4 depicts connectivity between a host machine and an NVD forproviding I/O virtualization for supporting multitenancy according tocertain embodiments. As depicted in FIG. 4 , host machine 402 executes ahypervisor 404 that provides a virtualized environment. Host machine 402executes two virtual machine instances, VM1 406 belonging tocustomer/tenant #1 and VM2 408 belonging to customer/tenant #2. Hostmachine 402 comprises a physical NIC 410 that is connected to an NVD 412via link 414. Each of the compute instances is attached to a VNIC thatis executed by NVD 412. In the embodiment in FIG. 4 , VM1 406 isattached to VNIC-VM1 420 and VM2 408 is attached to VNIC-VM2 422.

As shown in FIG. 4 , NIC 410 comprises two logical NICs, logical NIC A416 and logical NIC B 418. Each virtual machine is attached to andconfigured to work with its own logical NIC. For example, VM1 406 isattached to logical NIC A 416 and VM2 408 is attached to logical NIC B418. Even though host machine 402 comprises only one physical NIC 410that is shared by the multiple tenants, due to the logical NICs, eachtenant's virtual machine believes they have their own host machine andNIC.

In certain embodiments, each logical NIC is assigned its own VLAN ID.Thus, a specific VLAN ID is assigned to logical NIC A 416 for Tenant #1and a separate VLAN ID is assigned to logical NIC B 418 for Tenant #2.When a packet is communicated from VM1 406, a tag assigned to Tenant #1is attached to the packet by the hypervisor and the packet is thencommunicated from host machine 402 to NVD 412 over link 414. In asimilar manner, when a packet is communicated from VM2 408, a tagassigned to Tenant #2 is attached to the packet by the hypervisor andthe packet is then communicated from host machine 402 to NVD 412 overlink 414. Accordingly, a packet 424 communicated from host machine 402to NVD 412 has an associated tag 426 that identifies a specific tenantand associated VM. On the NVD, for a packet 424 received from hostmachine 402, the tag 426 associated with the packet is used to determinewhether the packet is to be processed by VNIC-VM1 420 or by VNIC-VM2422. The packet is then processed by the corresponding VNIC. Theconfiguration depicted in FIG. 4 enables each tenant's compute instanceto believe that they own their own host machine and NIC. The setupdepicted in FIG. 4 provides for I/O virtualization for supportingmulti-tenancy.

FIG. 5 depicts a simplified block diagram of a physical network 500according to certain embodiments. The embodiment depicted in FIG. 5 isstructured as a Clos network. A Clos network is a particular type ofnetwork topology designed to provide connection redundancy whilemaintaining high bisection bandwidth and maximum resource utilization. AClos network is a type of non-blocking, multistage or multi-tieredswitching network, where the number of stages or tiers can be two,three, four, five, etc. The embodiment depicted in FIG. 5 is a 3-tierednetwork comprising tiers 1, 2, and 3. The TOR switches 504 representTier-0 switches in the Clos network. One or more NVDs are connected tothe TOR switches. Tier-0 switches are also referred to as edge devicesof the physical network. The Tier-0 switches are connected to Tier-1switches, which are also referred to as leaf switches. In the embodimentdepicted in FIG. 5 , a set of “n” Tier-0 TOR switches are connected to aset of “n” Tier-1 switches and together form a pod. Each Tier-0 switchin a pod is interconnected to all the Tier-1 switches in the pod, butthere is no connectivity of switches between pods. In certainimplementations, two pods are referred to as a block. Each block isserved by or connected to a set of “n” Tier-2 switches (sometimesreferred to as spine switches). There can be several blocks in thephysical network topology. The Tier-2 switches are in turn connected to“n” Tier-3 switches (sometimes referred to as super-spine switches).Communication of packets over physical network 500 is typicallyperformed using one or more Layer-3 communication protocols. Typically,all the layers of the physical network, except for the TORs layer aren-ways redundant thus allowing for high availability. Policies may bespecified for pods and blocks to control the visibility of switches toeach other in the physical network so as to enable scaling of thephysical network.

A feature of a Clos network is that the maximum hop count to reach fromone Tier-0 switch to another Tier-0 switch (or from an NVD connected toa Tier-0-switch to another NVD connected to a Tier-0 switch) is fixed.For example, in a 3-Tiered Clos network at most seven hops are neededfor a packet to reach from one NVD to another NVD, where the source andtarget NVDs are connected to the leaf tier of the Clos network.Likewise, in a 4-tiered Clos network, at most nine hops are needed for apacket to reach from one NVD to another NVD, where the source and targetNVDs are connected to the leaf tier of the Clos network. Thus, a Closnetwork architecture maintains consistent latency throughout thenetwork, which is important for communication within and between datacenters. A Clos topology scales horizontally and is cost effective. Thebandwidth/throughput capacity of the network can be easily increased byadding more switches at the various tiers (e.g., more leaf and spineswitches) and by increasing the number of links between the switches atadjacent tiers.

In certain embodiments, each resource within CSPI is assigned a uniqueidentifier called a Cloud Identifier (CID). This identifier is includedas part of the resource's information and can be used to manage theresource, for example, via a Console or through APIs. An example syntaxfor a CID is:

-   -   ocid1.<RESOURCE TYPE>.<REALM>.[REGION][.FUTURE USE].<UNIQUE ID>        where,        ocid1: The literal string indicating the version of the CID;        resource type: The type of resource (for example, instance,        volume, VCN, subnet, user, group, and so on);        realm: The realm the resource is in. Example values are “c1” for        the commercial realm, “c2” for the Government Cloud realm, or        “c3” for the Federal Government Cloud realm, etc. Each realm may        have its own domain name;        region: The region the resource is in. If the region is not        applicable to the resource, this part might be blank;        future use: Reserved for future use.        unique ID: The unique portion of the ID. The format may vary        depending on the type of resource or service.        B—Example Layer 2 VLAN Architectures

This section describes techniques for providing Layer 2 networkingfunctionality in a virtualized cloud environment. The Layer 2functionality is provided in addition to and in conjunction with Layer 3networking functionality provided by the virtualized cloud environment.In certain embodiments, the virtual Layer 2 and Layer 3 functionality isprovided by Oracle Cloud Infrastructure (OCI) provided OracleCorporation.

After an introduction of the Layer 2 network functionalities, thesection describes the Layer 2 implementation of a VLAN. Thereafter, adescription of Layer 2 VLAN services is provided, including InternetGroup Management Protocol (IGMP) functionalities.

Introduction

The number of enterprise customers transitioning their on-premiseapplications to a cloud environment provided by a cloud servicesprovider (CSP) continues to increase rapidly. However, many of thesecustomers are quickly realizing that the road to transitioning to acloud environment can be quite bumpy requiring the customers torearchitect and reengineer their existing applications to make themworkable in the cloud environment. This is because applications writtenfor an on-premise environment often depend on features of the physicalnetwork for monitoring, availability, and scale. These on-premiseapplications thus need to be rearchitected and reengineered before theycan work in a cloud environment.

There are several reasons why on-premise applications cannot easilytransition to the cloud environment. One of the main reasons is thatcurrent cloud virtual networks operate at the Layer-3 of the OSI model,for example at the IP layer, and do not provide Layer-2 capabilities,which are needed by the application. Layer-3-based routing or forwardingincludes determining where a packet is to be sent (e.g., to whichcustomer instance) based upon information contained in the Layer-3header of the packet, for example, based upon the destination IP addresscontained in the Layer-3 header of the packet. To facilitate this, thelocation of IP addresses in the virtualized cloud network are determinedthrough a centralized control and orchestration system or controller.These may include, for example, IP addresses associated with customerentities or resources in the virtualized cloud environment.

Many customers run applications in their on-premise environments thathave strict requirements for Layer-2 networking capabilities whichcurrently are not addressed by current cloud offerings and IaaS serviceproviders. For example, traffic is current cloud offerings is routedusing Layer-3 protocols that use Layer-3 headers, and Layer-2 featuresneeded by the applications are not supported. These Layer-2 features mayinclude features such as Address Resolution Protocol (ARP) processing,Medium Access Controls (MAC) address learning, and Layer-2 broadcastcapabilities, Layer-2 (MAC based) forwarding, Layer-2 networkingconstructs, and others. By providing virtualized Layer-2 networkingfunctionality in the virtualized cloud network, as described in thisdisclosure, customers can now migrate their legacy applicationsseamlessly to the cloud environment without requiring any substantialrearchitecting or reengineering. For example, the virtualized Layer-2networking capabilities described herein enable such applications (e.g.,VMware vSphere, vCenter, vSAN and NSX-T components) to communicate atLayer-2 as they do in the on-premise environment. These applications areable to run the same versions and configurations in the public cloud,thereby enabling customers to use their legacy on-premise applicationsincluding existing knowledge, tools, and processes associated with thelegacy applications. Customers are also be able to access native cloudservices from their applications (e.g., using VMware Software DefinedData Center (SDDC)).

As another example, there are several legacy on-premise applications(e.g., enterprise clustering software applications, network virtualappliances) that require Layer-2 broadcast support for failover. Exampleapplications include Fortinet FortiGate, IBM QRadar, Palo Altofirewalls, Cisco ASA, Juniper SRX, and Oracle RAC (Real ApplicationClustering). By providing virtualized Layer-2 networking in thevirtualized public cloud as described in this disclosure, theseappliances are now able to run in a virtualized public cloud environmentunaltered. AS described herein, virtualized Layer-2 networkingfunctionality is provided that is comparable to on-premise. Thevirtualized Layer-2 networking functionality described in thisdisclosure supports traditional Layer-2 networking. This includessupport of customer-defined VLANs as well as unicast, broadcast, andmulticast Layer-2 traffic functions. Layer-2 based routing andforwarding of packets comprises using Layer-2 protocols and usinginformation contained in the Layer-2 header of a packet, for example,based upon the destination MAC address contained in the Layer-2 headerto route or forward the packet. Protocols used by enterpriseapplications (e.g., clustering software applications) such as ARP,Gratuitous Address Resolution Protocol (GARP), and Reverse AddressResolution Protocol (RARP) can also now work in the cloud environment.

There are several reasons why traditional virtualized cloudinfrastructures support virtualized Layer-3 networking and not Layer-2networking. Layer-2 networks typically do not scale as well as Layer-3networks. Layer-2 network control protocols do not have the level ofsophistication that is desired for scaling. For example, Layer-3networks do not have to worry about packet looping that Layer-2 networkshave to tackle. IP packets (i.e., Layer-3 packets) have the notion of atime to live (TTL), while Layer-2 packets do not. IP addresses,contained inside of Layer-3 packets, have a concept of topology, such assubnets, CIDR ranges, etc., while Layer-2 addresses (e.g., MACaddresses) do not. Layer-3 IP networks have inbuilt tools thatfacilitate troubleshooting, such as ping, traceroute, etc. for findingpath information. Such tools are not available for Layer-2. Layer-3networks support multi-pathing, which is not available at Layer-2.Because of the lack of sophisticated control protocols (e.g. BorderGateway Protocol (BGP) and Open Shortest Path First (OSPF)) especiallyfor exchanging information between entities in a network, Layer-2networks have to rely on broadcasting and multicasting in order to learnabout the network, which can adversely impact network performance. Asnetworks change, the learning process for Layer-2 has to be repeated,which is not needed at Layer-3. For these reasons and others, it is moredesirable for cloud IaaS service providers to provide infrastructuresthat operate at Layer-3 rather than at Layer-2.

However, in spite of its multiple shortcomings, Layer-2 functionality isneeded by many on-premise applications. For example, assume avirtualized cloud configuration where a customer (Customer 1) has twoinstances instance A with IP1 and instance B with IP2, in a virtualnetwork “V” where an instance may be a compute instance (e.g. baremetal, virtual machine or container) or a service instance such as aload balancer, nfs mount point, or other service instance. The virtualnetwork V is a distinct address space isolated from other virtualnetworks and the underlying physical network. For example, thisisolation may be achieved using various techniques including packetencapsulation or NAT. For this reason the IP address for an instance ina customer's virtual network is distinct from an address in the physicalnetwork where it is hosted. A centralized SDN (Software DefinedNetworking) control plane is provided that knows the physical IP andvirtual interfaces of all virtual IP addresses. When a packet is sentfrom instance A to a destination of IP2 in the virtual network V, thevirtual network SDN stack needs to know where IP2 is located. It has toknow this ahead of time so that it can send the packet to the IP in thephysical network where virtual IP address IP2 for V is hosted. Thelocation of a virtual IP address can be modified in the cloud thuschanging the relationship between a physical IP and virtual IP address.Whenever a virtual IP address is to be moved (e.g., an IP addressassociated with a virtual machine is to be moved to another virtualmachine or a virtual machine is migrated to a new physical host), an APIcall has to be made to the SDN control plane letting the controller knowthat the IP is being moved so that it can update all participants in theSDN stack including packet processors (data planes). There are classesof applications however that do not make such API calls. Examplesinclude various on-premise applications, applications provided byvarious virtualization software vendors such as VMware, and others. Thevalue of facilitating a virtual Layer-2 network in a virtualized cloudenvironment enables support for such applications that are notprogrammed to make such API calls or applications that rely on otherLayer-2 networking features, such as support for non-IP Layer-3 and MAClearning.

A virtual Layer-2 network creates a broadcast domain wherein learning isperformed by members of the broadcast domain. In a virtual Layer-2domain, there can be any IP on any MAC on any host within this Layer-2domain and the system will learn using standard Layer-2 networkingprotocols and the system will virtualize these networking primitives,without having to be explicitly told by a centralized controller as towhere MACs and IPs live in that virtual Layer-2 network. This enablesapplications to be run that need low latency failover, applications thatneed to support broadcast or multicast protocols to multiple nodes, andlegacy applications that do not know how to make API calls to a SDNcontrol plane or to an API endpoint to determine where IP and MACaddresses live. Providing Layer-2 networking capabilities in thevirtualized cloud environment is thus needed to be able to supportfunctionality that is not available at the IP Layer-3 level.

Another technical advantage of providing virtual Layer-2 in avirtualized cloud environment is that it enables various differentLayer-3 protocols (such as IPV4, IPV6) to be supported, including non-IPprotocols. For example, various non-IP protocols can be supported, suchas IPX, AppleTalk, and others. Because existing cloud IaaS providers donot provide Layer-2 functionality in their virtualized cloud networks,they cannot support these non-IP protocols. By providing Layer-2networking functionality as described in this disclosure, support can beprovided for protocols at Layer-3 and for applications that need andrely on the availability of Layer-2 level functionality.

Using the techniques described in this disclosure, both Layer-3 andLayer-2 functionality is provided in the virtualized cloudinfrastructure. As previously described, Layer-3 based networkingprovides certain efficiencies, especially well-suited for scaling, thatare not provided by Layer-2 networking. Providing Layer-2 functionalityin addition to Layer-3 functionality allows such efficiencies providedby Layer-3 to be leveraged (e.g., to provide more scalable solutions)while providing Layer-2 functionality in a more scalable way. Forexample, virtualized Layer-3 avoids having to use broadcasting forlearning purposes. By offering Layer-3 for its efficiencies, and at thesame time offering a virtualized Layer-2 for enabling those applicationsthat need it and applications that are not be able to function withouthaving Layer-2 functionality, and for supporting non-IP protocols, etc.,complete flexibility in the virtualized cloud environment is offered tocustomers.

Customers themselves have hybrid environments in which Layer-2environments exist along with Layer-3 environments, and the virtualizedcloud environment can now support both these environments. A customercan have Layer-3 networks such as subnets, and/or Layer-2 networks suchas VLANs, and these two environments can talk to each other in thevirtualized cloud environment.

The virtualized cloud environment also needs to support multitenancy.Multi-tenancy makes the provisioning of both Layer-3 functionality andLayer-2 functionality in the same virtualized cloud environmenttechnically difficult and complicated. For example, the Layer-2broadcast domain must be managed across many different customers in thecloud provider's infrastructure. The embodiments describe in thisdisclosure overcome these technical issues.

For a virtualization provider (e.g. VMware), a virtualized Layer-2network that emulates a physical Layer-2 network allows workloads to berun unaltered. Applications provided by such a virtualization providercan then run on the virtualized Layer-2 network provided by the cloudinfrastructure. For example, such applications may comprise a set ofinstances that need to run on a Layer-2 network. When a customer wantsto lift and shift such an application from their on-premise environmentto a virtualized cloud environment, they cannot just take theapplication and run it in the cloud because those applications rely onan underlying Layer-2 network (e.g., the Layer-2 network features areused to perform migration of virtual machines, or to move where MAC andIP addresses live), which is not provided by current virtualized cloudproviders. For these reasons, such applications cannot run natively in avirtualized cloud environment. Using the techniques described herein, acloud provider, in addition to providing a virtualized Layer-3 network,also provides a virtualized Layer-2 network. Now, such applicationstacks can run in the cloud environment unaltered and can run a nestedvirtualization in the cloud environment. Customers can now run their ownLayer-2 applications in the cloud and manage them. Application providersdo not have to make any changes to their software to facilitate this.Such legacy applications or workloads (e.g., legacy load balancers,legacy applications, KVMs, Openstack, clustering software) can now berun in the virtualized cloud environment unaltered.

By offering virtualized Layer-2 functionality as described herein,various Layer-3 protocols, including non-IP protocols, can be now besupported by the virtualized cloud environment. Taking Ethernet as anexample, various different EtherTypes (a field in the Layer-2 headerthat tells what type of Layer-3 packet is being sent; tells whatprotocol to expect at Layer-3) can be supported, including variousnon-IP protocols. EtherType is a two-octet field in an Ethernet frame.It is used to indicate which protocol is encapsulated in the payload ofthe frame and is used at the receiving end by the data link layer todetermine how the payload is processed. The EtherType is also used asthe basis of 802.1Q VLAN tagging, encapsulating packets from VLANs fortransmission multiplexed with other VLAN traffic over an Ethernet trunk.Examples of EtherTypes include IPV4, IPv6, Address Resolution Protocol(ARP), AppleTalk, IPX, and others. A cloud network that supports Layer-2protocols can support any protocol at the Layer-3 layer. In a similarmanner, when the cloud infrastructure provides support for a Layer-3protocol, it can support various protocols at Layer-4 such as TCP, UDP,ICMP, and others. The network can be agnostic to the Layer-4 protocolswhen virtualization is provided at Layer-3. Similarly, the network canbe agnostic to Layer-3 protocols when virtualization is provided atLayer-2. This technology can be extended to support any Layer-2 networktype, including FDDI, Infiniband, etc.

Accordingly, many applications written for physical networks, especiallyones that work with clusters of computer nodes that share a broadcastdomain use Layer-2 features that are not supported by in an L3 virtualnetwork. The following six examples highlight the complications that canresult from not providing Layer-2 networking capabilities:

(1) Assignment of MACs and IPs without a preceding API call. Networkappliances and Hypervisors (such as VMware) were not built for cloudvirtual networks. They assume they are able to use a MAC so long as itis unique and either get a dynamic address from a DHCP server or use anyIP that was assigned to the cluster. There is often no mechanism bywhich they can be configured to inform the control-plane about theassignment of these Layer-2 and Layer-3 addresses. If where the MACs andIPs are is not known, the Layer-3 virtual network does not know where tosend the traffic.(2) Low latency reassignment of MACs and IPs for high-availability andlive migration. Many on-premises applications use ARP to reassign IPsand MACs for high availability—when an instance in a cluster or HA pairstops responding, the newly active instance will send a Gratuitous ARP(GARP) to reassign a service IP to its MAC or a Reverse ARP (RARP) toreassign a service MAC to its interface. This is also important whenlive-migrating an instance on a hypervisor: the new host must send aRARP when the guest has migrated so that guest traffic is sent to thenew host. Not only is the assignment done without an API call, but italso needs to be extremely low latency (sub-millisecond). This cannot beaccomplished with HTTPS calls to a REST endpoint.(3) Interface multiplexing by MAC address. When hypervisors hostmultiple virtual machines on a single host, all of which are on the samenetwork, guest interfaces are differentiated by their MAC. This requiressupport for multiple MACs on the same virtual interface.(4) VLAN Support. A single physical virtual machine Host will need to beon multiple broadcast domains as indicated by the use of a VLAN tag. Forexample, VMware ESX uses VLANs for traffic separation (e.g. guestvirtual machines may communicate on one VLAN, storage on another, andhost virtual machines on yet another).(5) Use of broadcast and multicast traffic. ARP requires L2 broadcast,and there are examples of on-premises applications using broadcast andmulticast traffic for cluster and HA applications.(6) Support for Non-IP traffic. Since the L3 network requires the IPv4or IPv6 header to communicate, use of any L3 protocol other than IP willnot work. L2 virtualization means that the network within the VLAN canbe L3 protocol agnostic—the L3 header could by IPv4, IPv6, IPX, oranything else—even absent all together.Layer 2 VLAN Implementation

As disclosed herein, a Layer 2 (L2) network can be created within acloud network. This virtual L2 network includes one or several Layer 2virtual networks, such as virtualized L2 VLANs which are referred toherein as VLANs. Each VLAN can include a plurality of compute instances,each of which can be associated with at least one L2 virtual networkinterface (e.g., a L2 VNIC) and an L2 virtual switch. In someembodiments, each pair of L2 virtual network interface and L2 virtualswitch is hosted on an NVD. An NVD may host multiple of such pairs,where each pair is associated with a different compute instance. Thecollection of L2 virtual switches represent an emulated single L2 switchof the VLAN. The L2 virtual network interfaces represent a collection ofL2 ports on the emulated single L2 switch. The VLAN can be connected,via a VLAN Switching and Routing Service (VSRS), also referred to hereinas, a Real Virtual Router (RVR) or as an L2 VSRS, to other VLANs, Layer3 (L3) networks, on-premise networks, and/or other networks. An exampleof this architecture is described herein below.

With reference now to FIG. 6 , a schematic illustration of oneembodiment of a computing network is shown. A VCN 602 resides in a CSPI601. The VCN 602 includes a plurality gateways connecting the VCN 602 toother networks. These gateways include a DRG 604 which can connect theVCN 602 to, for example, an on-premise network such as on-premise datacenter 606. The gateways can further include a gateway 600, which caninclude, for example, a LPG for connecting the VCN 602 with another VCN,and/or an IGW and/or NAT gateway for connecting the VCN 602 to theinternet. The gateways of the VCN 602 can further include a servicesgateway 610 which can connect the VCN 602 with a services network 612.The services network 612 can include one or several databases and/orstores including, for example, autonomous database 614 and/or objectstore 616. The services network can comprise a conceptual networkcomprising an aggregation of IP ranges, which can be, for example,public IP ranges. In some embodiments, these IP ranges can cover some orall of the public services offered by the CSPI 601 provider. Theseservices can, for example, be accessed through an Internet Gateway orNAT Gateway. In some embodiments, the services network provides a wayfor the services in the services network to be accessed from the localregion through a dedicated gateway for that purpose (a Service Gateway).In some embodiments, the backends of these services can be implementedin, for example, their own private networks. In some embodiments, theservices network 612 can include further additional databases.

The VCN 602 can include a plurality of virtual networks. These networkscan, each include one or several compute instances which can communicatewithin their respective networks, between networks, or outside of theVCN 602. One of the virtual networks of the VCN 602 is an L3 subnet 620.The L3 subnet 620 is a unit of configuration or a subdivision createdwithin the VCN 602. The subnet 620 can comprise a virtual Layer 3network in the virtualized cloud environment of the VCN 602, which VCN602 is hosted on the underlying physical network of CPSI 601. AlthoughFIG. 6 depicts a single subnet 620, the VCN 602 can have one or multiplesubnets. Each subnet within the VCN 602 can be associated with acontiguous range of overlay IP addresses (e.g., 10.0.0.0/24 and10.0.1.0/24) that do not overlap with other subnets in that VCN andwhich represent an address space subset within the address space of theVCN. In some embodiments, this IP address space can be isolated from anaddress space associated with CPSI 601.

The subnet 620 includes one or more compute instances, and specificallyincludes a first compute instance 622-A and a second compute instance622-B. The compute instances 622-A, 622-B can communicate with eachother within the subnet 620, or they can communicate with otherinstances, devices, and/or networks outside of the subnet 620.Communication outside of the subnet 620 is enabled by a virtual router(VR) 624. The VR 624 enables communications between the subnet 620 andother networks of the VCN 602. For the subnet 620, the VR 624 representsa logical gateway that enables the subnet 620 (e.g., the computeinstances 622-A, 622-B) to communicate with endpoints on other networkswithin the VCN 602, and with other endpoints outside the VCN 602.

The VCN 602 can further include additional networks, and specificallycan include one or several L2 VLANs (referred to herein as VLANs), whichare examples of a virtual L2 network. These one or several VLANs caneach comprise a virtual Layer 2 network that is localized in the cloudenvironment of the VCN 602 and/or that is hosted by the underlyingphysical network of the CPSI 601. In the embodiment of FIG. 6 , the VCN602 includes a VLAN A 630 and a VLAN B 640. Each VLAN 630, 640 withinthe VCN 602 can be associated with a contiguous range of overlay IPaddresses (e.g., 10.0.0.0/24 and 10.0.1.0/24) that do not overlap withother networks in that VCN, such as other subnets or VLANs in that VCN,and which represent an address space subset within the address space ofthe VCN. In some embodiments, this IP address space of the VLAN can beisolated from an address space associated with CPSI 601. Each of theVLANs 630, 640 can include one or several compute instances, andspecifically, the VLAN A 630 can include, for example, a first computeinstance 632-A, and a second compute instance 632-B. In some embodimentsthe VLAN A 630 can include additional compute instances. The VLAN B 640can include, for example, a first compute instance 642-A, and a secondcompute instance 642-B. Each of the compute instances 632-A, 632-B,642-A, 642-B can have an IP address and a MAC address. These addressescan be assigned or generated in any desired manner. In some embodiments,these addresses can be within a CIDR of the VLAN of the computeinstances, and in some embodiments, these addresses can be anyaddresses. In embodiments in which compute instances of a VLANcommunicate with endpoints outside of the VLAN, then one or both ofthese addresses are from the VLAN CIDR, whereas when all communicationsare intra-VLAN, then these addresses are not limited to addresses withinthe VLAN CIDR. In contrast to a network in which addresses are assignedby a control plane, the IP and/or MAC addresses of the compute instancesin the VLAN can be assigned by the user/customer of that VLAN, and theseIP and/or MAC addresses can then be discovered and/or learned by thecompute instances in the VLAN according to the processes for learningdiscussed below.

Each of the VLANs can include a VLAN Switching and Routing Service(VSRS), and specifically, the VLAN A 630 includes a VSRS A 634 and theVLAN B 640 includes a VSRS B 644. Each VSRS 634, 644 participates inLayer 2 switching and local learning within a VLAN and also performs allnecessary Layer 3 network functions including ARP, NDP, and routing.VSRS performs ARP (which is a Layer 2 protocol) as the VSRS has to mapIPs to MACs.

In these cloud-based VLANs, each virtual interface or virtual gatewaycan be associated with one or more media access control (MAC) addresses,which can be virtual MAC addresses. Within the VLAN, the one or severalcompute instances 632-A, 632-B, 642-A, 642-B, which can be, for examplebare metal, VM, or container, and/or one or several service instances,can directly communicate with each other via a virtual switch.Communication outside of the VLAN, such as with other VLANs or with anL3 network is enabled via the VSRS 634, 644. The VSRS 634, 644 is adistributed service providing the Layer 3 functions, such as IP routing,for a VLAN network. In some embodiments, the VSRS 634, 644 is ahorizontally scalable, highly available routing service that can sit atthe intersection of IP networks and L2 networks and participate in IProuting and L2 learning within a cloud-based L2 domain.

The VSRS 634, 644 can be distributed across multiple nodes within theinfrastructure, and the VSRS 634, 644 function can be scalable, andspecifically can be horizontally scalable. In some embodiments, each ofthe nodes implementing the function of the VSRS 634, 644 share andreplicate the function of a router and/or a switch with each other.Further, these nodes can present themselves as a single VSRS 634, 644 toall of the instances in the VLAN 630, 640. The VSRS 634, 644 can beimplemented on any virtualization device within the CSPI 601, andspecifically within the virtual network. Thus, in some embodiments, theVSRS 634, 644 can be implemented on any of the virtual networkvirtualization devices including NICs, SmartNICs, switches, Smartswitches or general compute hosts.

The VSRS 634, 644 can be a service residing on one or several hardwarenodes, such as one or several servers, such as for example, one orseveral x86 servers, or one or several networking devices, such as oneor several NICs and specifically one or several SmartNICs, supportingthe cloud network. In some embodiments, the VSRS 634, 644 can beimplemented on a server fleet. Thus, the VSRS 634, 644 can be a servicedistributed across a fleet of nodes, which may be a centrally managedfleet or may be distributed to the edges, of virtual networkingenforcers that participates in and shares L2 and L3 learning along withevaluating routing and security policies. In some embodiments each ofthe VSRS instances can update other VSRS instances with new mappinginformation as this new mapping information is learned by a VSRSinstance. For example, when a VSRS instance learns IP, interface, and/orMAC mapping for one or several CIs in its VLAN, the VSRS instance canprovide that updated information to other VSRS instances within the VCN.Via this cross-updating, a VSRS instance associated with a first VLANcan know the mappings, including IP, interface, and/or MAC mappings forCIs in other VLANs, in some embodiments, for CIs in other VLANs withinthe VCN 602. When the VSRS resides on a server fleet and/or isdistributed across a fleet of nodes, these updates can be greatlyexpedited.

In some embodiments, the VSRS 634, 644 may also host one or severalhigher level services necessary for networking including, but notlimited to: a DHCP relay; a DHCP (hosting); a DHCPv6; a neighbordiscovery protocol such as IPv6 Neighbor Discovery Protocol; DNS; ahosting DNSv6; a SLAAC for IPv6; a NTP; a metadata service; and ablockstore mount points. In some embodiments, the VSRS can support oneor several Network Address Translation (NAT) functions to translatebetween network address spaces. In some embodiments, the VSRS canincorporate anti-spoofing, anti-MAC spoofing, ARP-cache poisoningprotection for IPv4, IPv6 Route Advertisement (RA) guarding, DHCPguarding, packet filtering using Access Control Lists (ACLs); and/orreverse path forwarding checks. The VSRS can implement functionsincluding, for example, ARP, GARP, Packet Filters (ACLs), DHCP relay,and/or IP routing protocols. The VSRS 634, 644 can, for example, learnMAC addresses, invalidate expired MAC addresses, handle moves of MACaddresses, vet MAC address information, handling flooding of MACinformation, handling of storm control, loop prevention, Layer 2multicast via, for example, protocols such as IGMP in the cloud,statistic gathering including logs, statistics using SNMP, monitoring,and/or gathering and using statistics for broadcast, total traffic,bits, spanning tree packets, or the like.

Within the virtual network, the VSRS 634, 644 can manifest as differentinstantiations. In some embodiments, each of these instantiations of theVSRS can be associated with a VLAN 630, 640, and in some embodimentseach VLAN 630, 640 can have an instantiation of the VSRS 634, 644. Insome embodiments, each instantiation of the VSRS 634, 644 can have oneor several unique tables corresponding to the VLAN 630, 640 with whichthe instantiation of the VSRS 634, 644 is associated. Each instantiationof the VSRS 634, 644 can generate and/or curate the unique tablesassociated with that instantiation of the VSRS 634, 644. Thus, while asingle service may provide VSRS 634, 644 functionality for one orseveral cloud networks, individual instantiations of the VSRS 634, 644within the cloud network can have unique Layer 2 and Layer 3 forwardingtables, while multiple such customer networks can have over-lappingLayer 2 and Layer 3 forwarding tables.

In some embodiments, the VSRS 634, 644 can support conflicting VLAN andIP spaces across multiple tenants. This can include having multipletenants on the same VSRS 634, 644. In some embodiments, some or all ofthese tenants could choose to use some or all of: the same IP addressspace, the same MAC space, and the same VLAN space. This can provideextreme flexibility for users in choosing addresses. In someembodiments, this multitenancy is supported via providing each tenantwith a distinct virtual network, which virtual network is a privatenetwork within the cloud network. Each virtual network is given a uniqueidentifier. Similarly, in some embodiments, each host can have a uniqueidentifier, and/or each virtual interface or virtual gateway can have aunique identifier. In some embodiments, these unique identifiers, andspecifically the unique identifier of the virtual network for a tenantcan be encoded in each communication. By providing each virtual networkwith a unique identifier and including this within communications, asingle instantiation of the VSRS 634, 644 can service multiple tenantshaving overlapping address and/or name spaces.

The VSRS 634, 644 can perform these switching and/or routing functionsto facilitate and/or enable the creation and/or communication with an L2network within the VLAN 630, 640. This VLAN 630, 640 can be found withina cloud computing environment, and more specifically within a virtualnetwork in that cloud computing environment.

For example, each of VLAN 630, 640 include multiple compute instances632-A, 632-B, 642-A, 642-B. The VSRS 634, 644 enables communicationbetween a compute instance in one VLAN 630, 640 with a compute instancein another VLAN 630, 640 or in the subnet 620. In some embodiments, theVSRS 634, 644 enables communication between a compute instance in oneVLAN 630, 640 with another VCN, another network outside of the VCNincluding the internet, an on-premise data center, or the like. In suchan embodiment, for example, a compute instance, such as compute instance632-A, can send a communication to an endpoint outside of the VLAN, inthis instance, outside of VLAN A 630. The compute instance (632-A) cansend a communication to VSRS A 634, which can direct the communicationto a router 624, 644 or gateway 604, 608, 610 communicatively coupledwith the desired endpoint. The router 624, 644 or gateway 604, 608, 610communicatively coupled with the desired endpoint can receive thecommunication from the compute instance (632-A) and can direct thecommunication to the desired endpoint.

With reference now to FIG. 7 , a logical and hardware schematicillustration of a VLAN 700 is shown. As seen, the VLAN 700 includes aplurality of endpoints, and specifically includes a plurality of computeinstances and a VSRS. The plurality of compute instances (CIs) areinstantiated on one or several host machines. In some embodiments, thiscan be in a one-to-one relationship such that each CI is instantiated ona unique host machine, and/or in some embodiments, this can be in amany-to-one relationship such that a plurality of CIs are instantiatedon a single, common host machine. In the various embodiments, the CIscan be Layer 2 CIs by being configured to communicate with each otherusing L2 protocols. FIG. 7 depicts a scenario in which some CIs areinstantiated on unique host machines and in which some CIs share acommon host machine. As seen in FIG. 7 , Instance 1 (CI1) 704-A isinstantiated on host machine 1 702-A, instance 2 (CL2) 704-B isinstantiated on host machine 2 702-B, and instances 3 (CI3) 704-C andinstance 4 (CI4) 704-D are instantiated on a common host machine 702-C.

Each of the CIs 704-A, 704-B, 704-C, 704-D is communicatively coupledwith other CIs 704-A, 704-B, 704-C, 704-D in the VLAN 700 and with VSRS714. Specifically, each of the CIs 704-A, 704-B, 704-C, 704-D isconnected to the other CIs 704-A, 704-B, 704-C, 704-D in the VLAN 700and to the VSRS 714 via an L2 VNIC and a switch. Each CI 704-A, 704-B,704-C, 704-D is associated with a unique L2 VNIC and a switch. Theswitch can be an L2 virtual switch that is local and uniquely associatedwith and deployed for the L2 VNIC. Specifically, CI1 704-A is associatedwith L2 VNIC 1 708-A and switch 1 710-A, CL2 704-B is associated with L2VNIC 2 708-B and switch 710-B, CI3 704-C is associated with L2 VNIC 3708-C and switch 3 710-C, and CI4 704-D is associated with L2 VNIC 4708-D and switch 4 710-D.

In some embodiments, each L2 VNIC 708 and its associated switch 710 canbe instantiated on an NVD 706. This instantiation can be in a one-to-onerelationship such that a single L2 VNIC 708 and its associated switch710 are instantiated on a unique NVD 706, or this instantiation can bein a many-to-one relationship such that multiple L2 VNICs 708 and theirassociated switches 710 are instantiated on a single, common NVD 706.Specifically, L2 VNIC 1 708-A and switch 1 710-A are instantiated on NVD1 706-A, L2 VNIC 2 708-B and switch 2 710-B are instantiated on NVD 2,and both L2 VNIC 3 708-C and switch 3 710-C, and L2 VNIC 4 708-D, andswitch 710-D are instantiated on a common NVD, namely, NVD 706-C.

In some embodiments, the VSRS 714 can support conflicting VLAN and IPspaces across multiple tenants. This can include having multiple tenantson the same VSRS 714. In some embodiments, some or all of these tenantscould choose to use some or all of: the same IP address space, the sameMAC space, and the same VLAN space. This can provide extreme flexibilityfor users in choosing addresses. In some embodiments, this multitenancyis supported via providing each tenant with a distinct virtual network,which virtual network is a private network within the cloud network.Each virtual network (e.g., each VLAN or VCN) is given a uniqueidentifier, such as a VCN identifier which can be a VLAN identifier.This unique identifier can be selected by, for example, the controlplane, and specifically by the control plane of the CSPI. In someembodiments, this unique VLAN identifier can comprise one or severalbits that can be included and/or used in packet encapsulation.Similarly, in some embodiments, each host can have a unique identifier,and/or each virtual interface or virtual gateway can have a uniqueidentifier. In some embodiments, these unique identifiers, andspecifically the unique identifier of the virtual network for a tenantcan be encoded in each communication. By providing each virtual networkwith a unique identifier and including this within communications, asingle instantiation of the VSRS can service multiple tenants havingoverlapping address and/or name spaces. In some embodiments, a VSRS 714can determine to which tenant a packet belongs based on the VCNidentifier and/or the VLAN identifier associated with a communication,and specifically inside of the VCN header of the communication. Inembodiments disclosed herein, a communication leaving or entering a VLANcan have a VCN header which can include a VLAN identifier. Based on theVCN header containing the VLAN identifier, the VSRS 714 can determinetenancy, or in other words, the recipient VSRS can determine to whichVLAN and/or to which tenant to send the communication. In addition, eachcompute instance that belongs to a VLAN (e.g., an L2 compute instance)is given a unique interface identifier that identifies the L2 VNIC thatis associated with the compute instance. The interface identifier can beincluded in traffic from and/or to the computer instance (e.g., by beingincluded in a header of a frame) and can be used by an NVD to identifythe L2 VNIC associated with the compute instance. In other words, theinterface identifier can uniquely indicate the compute instance and/orits associated L2 VNIC.

As indicated in FIG. 7 , the switches 710-A, 710-B, 710-C, 710-D cantogether form an L2 distributed switch 712, also referred to herein asdistributed switch 712. From a customer standpoint, each switch 710-A,710-B, 710-C, 710-D in the L2 distributed switch 712 is a single switchthat connects to all of the CIs in the VLAN. However, the L2 distributedswitch 712, which emulates the user experience of a single switch, isinfinitely scalable and includes a collection of local switches (e.g.,in the illustrative example of FIG. 7 , the switches 710-A, 710-B,710-C, 710-D). As shown in FIG. 7 , each CI executes on a host machineconnected to a NVD. For each CI on a host connected to an NVD, the NVDhosts a Layer 2 VNIC and a local switch associated with the computeinstance (e.g., an L2 virtual switch, local to the NVD, associated withthe Layer 2 VNIC, and being one member or component of the L2distributed switch 712). The Layer 2 VNIC represents a port of thecompute instance on the Layer 2 VLAN. The local switch connects the VNICto other VNICs (e.g., other ports) associated with other computeinstances of the Layer 2 VLAN.

Each of the CIs 704-A, 704-B, 704-C, 704-D can communicate with theothers of the CIs 704-A, 704-B, 704-C, 704-D in the VLAN 700 or with theVSRS 714. One of CIs 704-A, 704-B, 704-C, 704-D sends a frame to anotherof the CIs 704-A, 704-B, 704-C, 704-D or to the VSRS 714 by sending theframe to the MAC address and the interface identifier of the recipientone of the CIs 704-A, 704-B, 704-C, 704-D or the VSRS 714. The MACaddress and the interface identifier can be included in a header of theframe. As explained herein above, the interface identifier can indicatethe L2 VNIC of the recipient one of the CIs 704-A, 704-B, 704-C, 704-Dor of the VSRS 714.

In one embodiment, the CI1 704-A can be a source CI, the L2 VNIC 708-Acan be a source L2 VNIC, and the switch 710-A can be a source L2 virtualswitch. In this embodiment, CI3 704-C can be the destination CI, and theL2 VNIC 3 708-C can be the destination L2 VNIC. The source CI can send aframe with a source MAC address and a destination MAC address. Thisframe can be intercepted by the NVD 706-A instantiating the source VNICand the source switch.

The L2 VNICs 708-A, 708-B, 708-C, 708-D can, for the VLAN 700, eachlearn mapping of MAC addresses to interface identifiers of the L2 VNICs.This mapping can be learned based on frames and/or communicationsreceived from within the VLAN 700. Based on this previously determinedmapping, the source VNIC can determine the interface identifier of thedestination interface associated with the destination CI within theVLAN, and can encapsulate the frame. In some embodiments, thisencapsulation can comprise a GENEVE encapsulation, and specifically anL2 GENEVE encapsulation, which encapsulation include the L2 (Ethernet)header of the frame being encapsulated. The encapsulated frame canidentify the destination MAC, the destination interface identifier, thesource MAC, and the source interface identifier.

The source VNIC can pass the encapsulated frame to the source switch,which can direct the frame to the destination VNIC. Upon receipt of theframe, the destination VNIC can decapsulate the frame and can thenprovide the frame to the destination CI.

With reference now to FIG. 8 , a logical schematic illustration ofmultiple connected L2 VLANs 800 is shown. In the specific embodimentdepicted in FIG. 8 , both VLANs are located in the same VCN. As seen,the multiple connected L2 VLANs 800 can include a first VLAN, VLAN A802-A and a second VLAN, VLAN B 802-B. Each of these VLANs 802-A, 802-Bcan include one or several CIs, each of which can have an associated L2VNIC and an associated L2 virtual switch. Further, each of these VLANs802-A, 802-B can include a VSRS.

Specifically, VLAN A 802-A can include instance 1 804-A connected to L2VNIC 1 806-A and switch 1 808-A, instance 2 804-B connected to L2 VNIC 2806-B and switch 808-B, and instance 3 804-C connected to L2 VNIC 3806-C and switch 3 808-C. VLAN B 802-B can include instance 4 804-Dconnected to L2 VNIC 4 806-D and switch 4 808-D, instance 5 804-Econnected to L2 VNIC 5 806-E and switch 808-E, and instance 6 804-Fconnected to L2 VNIC 6 806-F and switch 3 808-F. VLAN A 802-A canfurther include VSRS A 810-A, and VLAN B 802-B can include VSRS B 810-B.Each of the CIs 804-A, 804-B, 804-C of VLAN A 802-A can becommunicatively coupled to VSRS A 810-A, and each of the CIS 804-D,804-E, 804-F of VLAN B 802-B can be communicatively coupled to VSRS B810-B.

The VLAN A 802-A can be communicatively coupled to the VLAN B 802-B viatheir respective VSRS 810-A, 810-B. Each VSRS can likewise be coupled toa gateway 812, which can provide access to CIs 804-A, 804-B, 804-C,804-D, 804-E, 804-F in each VLAN 802-A, 802-B to other networks outsideof the VCN in which the VLANs are 802-A, 802-B are located. In someembodiments, these networks can include, for example, one or severalon-premise networks, another VCN, a services network, a public networksuch as the interne, or the like.

Each of the CIs 804-A, 804-B, 804-C in the VLAN A 802-A can communicatewith the CIs 804-D, 804-E, 804-F in the VLAN B 802-B via the VSRS 810-A,810-B of each VLAN 802-A, 802-B. For example, one of CIs 804-A, 804-B,804-C, 804-D, 804-E, 804-F in one of the VLANs 802-A, 802-B can send aframe to a CI 804-A, 804-B, 804-C, 804-D, 804-E, 804-F in the other ofthe VLANs 802-A, 802-B. This frame can exit the source VLAN via the VSRSof the source VLAN and can enter the destination VLAN, and be routed tothe destination CI via the destination VSRS.

In one embodiment, the CI 1 804-A can be a source CI, the VNIC 806-A canbe a source VNIC, and a switch 808-A can be a source switch. In thisembodiment, the CI 5 804-E can be the destination CI, and the L2 VNIC 5806-E can be the destination VNIC. The VSRS A 810-A can be the sourceVSRS identified as SVSRS, and the VSRS B 810-B can be the destinationVSRS, identified as DVSRS.

The source CI can send a frame with a MAC address. This frame can beintercepted by the NVD instantiating source VNIC and the source switch.The source VNIC, encapsulates the frame. In some embodiments, thisencapsulation can comprise a GENEVE encapsulation, and specifically anL2 GENEVE encapsulation. The encapsulated frame can identify adestination address of the destination CI. In some embodiments, thisdestination address can also comprise a destination address of thedestination VSRS. The destination address of the destination CI caninclude a destination IP address, a destination MAC of the destinationCI, and/or a destination interface identifier of the destination VNICassociated with the destination CI. The destination address of thedestination VSRS can include the IP address of the destination VSRS, aninterface identifier of the destination VNIC associated with thedestination VSRS, and/or the MAC address of the destination VSRS.

The source VSRS can receive the frame from the source switch, can lookup the VNIC mapping from the destination address of the frame, whichdestination address can be a destination IP address, and can forward thepacket to the destination VSRS. The destination VSRS can receive theframe. Based on the destination address contained in the frame, thedestination VSRS can forward the frame to the destination VNIC. Thedestination VNIC can receive and decapsulate the frame and can thenprovide the frame to the destination CI.

With reference now to FIG. 9 , a logical schematic illustration ofmultiple connected L2 VLANs and a subnet 900 is shown. In the specificembodiment depicted in FIG. 9 , both VLANs and the subnet are located inthe same VCN. This is indicated as the virtual router and the VSRS ofboth of the VLANs and the subnet are directly connected, as opposed toconnected through a gateway.

As seen, this can include a first VLAN, VLAN A 902-A, a second VLAN,VLAN B 902-B, and subnet 930. Each of these VLANs 902-A, 902-B caninclude one or several CIs, each of which can have an associated L2 VNICand an associated L2 switch. Further, each of these VLANs 902-A, 902-Bcan include a VSRS. Likewise, the subnet 930, which can be an L3 subnet,can include one or several CIs, each of which can have an associated L3VNIC, and the L3 subnet 930 can include a virtual router 916.

Specifically, the VLAN A 902-A can include instance 1 904-A connected toL2 VNIC 1 906-A and switch 1 908-A, instance 2 904-B connected to L2VNIC 2 906-B and switch 908-B, and instance 3 904-C connected to L2 VNIC3 906-C and switch 3 908-C. VLAN B 902-B can include instance 4 904-Dconnected to L2 VNIC 4 906-D and switch 4 908-D, instance 5 904-Econnected to L2 VNIC 5 906-E and switch 908-E, and instance 6 904-Fconnected to L2 VNIC 6 906-F and switch 3 908-F. The VLAN A 902-A canfurther include a VSRS A 910-A, and the VLAN B 902-B can include a VSRSB 910-B. Each of the CIs 904-A, 904-B, 904-C of VLAN A 902-A can becommunicatively coupled to the VSRS A 910-A, and each of the CIs 904-D,904-E, 904-F of VLAN B 902-B can be communicatively coupled to the VSRSB 910-B. The L3 subnet 930 can include one or several CIs, andspecifically can include instance 7 904-G, which is communicativelycoupled to L3 VNIC 7 906-G. The L3 subnet 930 can include a virtualrouter 916.

The VLAN A 902-A can be communicatively coupled to the VLAN B 902-B viatheir respective VSRS 910-A, 910-B. The L3 subnet 930 can becommunicatively coupled with the VLAN A 902-A and VLAN B 902-B via thevirtual router 916. Each of the virtual router 916 and VSRS instances910-A, 910-B can likewise be coupled to a gateway 912, which can provideaccess for CIs 904-A, 904-B, 904-C, 904-D, 904-E, 904-F, 904-G in eachVLAN 902-A, 902-B and in the subnet 930 to other networks outside of theVCN in which the VLANs are 902-A, 902-B and subnet 930 are located. Insome embodiments, these networks can include, for example, one orseveral on-premise networks, another VCN, a services network, a publicnetwork such as the internet, or the like.

Each VSRS instance 910-A, 910-B can provide an egress pathway for framesleaving the associated VLAN 902-A, 902-B, and an ingress pathway forframes entering the associated VLAN 902-A, 902-B. From the VSRS instance910-A, 910-B of a VLAN 902-A, 902-B, frames can be sent to any desiredendpoint, including an L2 endpoint such as an L2 CI in another VLANeither on the same VCN or on a different VCN or network, and/or to an L3endpoint such as an L3 CI in a subnet either on the same VCN or one adifferent VCN or network.

In one embodiment, the CI 1 904-A can be a source CI, the VNIC 906-A canbe a source VNIC, and the switch 908-A can be a source switch. In thisembodiment, the CI 7 904-G can be the destination CI, and the VNIC 7906-G can be the destination VNIC. VSRS A 910-A can be the source VSRSidentified as SVSRS, and the virtual router (VR) 916 can be thedestination VR.

The source CI can send a frame with a MAC address. This frame can beintercepted by the NVD instantiating the source VNIC and the sourceswitch. The source VNIC, encapsulates the frame. In some embodiments,this encapsulation can comprise a GENEVE encapsulation, and specificallyan L2 GENEVE encapsulation. The encapsulated frame can identify adestination address of the destination CI. In some embodiments, thisdestination address can also comprise a destination address of the VSRSof the VLAN of the source CI. The destination address of the destinationCI can include a destination IP address, a destination MAC of thedestination CI, and/or a destination interface identifier of thedestination VNIC of the destination CI.

The source VSRS can receive the frames from the source switch, can lookup the VNIC mapping from the destination address of the frame, whichdestination address can be a destination IP address, and can forward theframe to the destination VR. The destination VR can receive the frame.Based on the destination address contained in the frame, the destinationVR can forward the frame to the destination VNIC. The destination VNICcan receive and decapsulate the frame and can then provide the frame tothe destination CI.

Learning by an L2 VNIC and/or an L2 Virtual Switch within a Virtual L2Network

With reference now to FIG. 10 , a schematic illustration of oneembodiment of intra-VLAN communication and learning within a VLAN 1000is shown. The learning here is specific to how an L2 VNIC, VSRS of theVLAN of the source CI, and/or an L2 virtual switch learn associationsbetween MAC addresses and L2 VNICs//VSRS VNICs (more specifically,between MAC addresses associated with L2 compute instances or a VSRS andinterface identifiers associated with L2 VNICS of these L2 computeinstances associated with a VSRS VNIC). Generally, the learning is basedon ingress traffic. This learning, for an aspect of interface-to-MACaddress learning is different from a learning process (e.g., an ARPprocess) that an L2 compute instance may implement to learn adestination MAC address. The two learning processes (e.g., of an L2VNIC/L2 virtual switch and of an L2 compute instance) are illustrated asbeing jointly implemented in FIG. 12 .

As seen, the VLAN 1000 includes compute instance 1 1000-Acommunicatively coupled with NVD 1 1001-A which instantiates L2 VNIC 11002-A and L2 switch 1 1004-A. The VLAN 1000 also include computeinstance 2 1000-B communicatively coupled with NVD 2 1001-B whichinstantiates L2 VNIC 2 1002-B and L2 switch 2 1004-A. The VLAN 1000 alsoincludes VSRS 1015 running on a server fleet, and which includes VSRSVNIC 1002-C and VSRS switch 1004-C. All of the switches 1004-A, 1004-B,1004-C together form an L2 distributed switch 1050. The VSRS 1015 iscommunicatively coupled with an endpoint 1008 which can comprise agateway, and specifically can comprise L2/L3 router in, for example, theform of another VSRS, or an L3 router in, for example, the form of avirtual router.

A control plane 1010 of a VCN hosting the VLAN 1000 maintainsinformation identifying each L2 VNIC on the VLAN 1000 and networkplacement of the L2 VNIC. For example, this information can include foran L2 VNIC, the interface identifier associated with the L2 VNIC, and/orthe physical IP address of the NVD hosting the L2 VNIC. The controlplane 1010 updates (e.g., periodically or on demand) interfaces in theVLAN 1000 with this information. Thus, each L2 VNIC 1002-A, 1002-B,1002-C in the VLAN 1000 receives the information from the control plane1010 identifies the interfaces in the VLAN, and populates a table withthis information. The table populated by an L2 VNIC can be storedlocally to the NVD hosting the L2 VNIC. In the event that a VNIC 1002-A,1002-B, 1002-C already includes a current table, the VNIC 1002-A,1002-B, 1002-C can determine any discrepancy between the VNIC's 1002-A,1002-B, 1002-C current table and the information/table received from thecontrol plane 1010. The VNIC 1002-A, 1002-B, 1002-C can, in someembodiments, update its table to match information received from thecontrol plane 1010.

As seen in FIG. 10 , frames are sent via an L2 switch 1004-A, 1004-B,1004-C, and are received by a recipient VNIC 1002-A, 1002-B, 1002-C. Asframes are received by a VNIC 1002-A, 1002-B, 1002-C, that VNIC learnsthe mapping of the source interface (source VNIC) and source MAC addressof that frame. Based on its table of information received from thecontrol plane 1010, the VNIC can map the source MAC address (from areceived frame) to an interface identifier of the source VNIC and the IPaddress of the VNIC and/or IP address of the NVD hosting the VNIC (wherethe interface identifier and IP address(es) are available from thetable). As such, an L2 VNIC 1002-A, 1002-B, 1002-C learns mapping ofinterface identifiers to MAC addresses based on received communicationsand/or frames. Each VNIC 1002-A, 1002-B, 1002-C can its L2 forwarding(FWD) table 1006-A, 1006-B, 1006-C with this learned mappinginformation. In some embodiments, an L2 forwarding table includes andassociates a MAC address with at least one of an interface identifier,or a physical IP address. In such embodiments, the MAC address is anaddress assigned to an L2 compute instance and can correspond to a portemulated by an L2 VNIC associated with the L2 compute instance. Theinterface identifier can uniquely identify the L2 VNIC and/or the L2compute instance. The virtual IP address can be that of the L2 VNIC. Andthe physical IP address can be that of the NVD hosting the L2 VNIC. TheL2 forwarding updated by an L2 VNIC can be stored locally on the NVDhosting the L2 VNIC and used by the L2 virtual switch associated withthe L2 VNIC to direct frames. In some embodiments, VNICs within a commonVLAN can share all or portions of their mapping table with each other.

In light of the above network architecture, traffic flows are describedherein next. In the interest of clarity of explanation, the trafficflows are described in connection with compute instance 2 1000-B, L2VNIC 2 10002-B, L2 switch 2 1004-B, and NVD 2 1001-B. The descriptionequivalently applies to traffic flows to and/or from other computeinstances.

As explained herein above, the VLAN is implemented within a VCN as anoverlay L2 network on top of an L3 physical network. An L2 computeinstance of the VLAN can send or receive an L2 frame that includesoverlay MAC addresses (also referred to as virtual MAC addresses) assource and destination MAC addresses. The L2 frame can also encapsulatea packet that includes overlay IP addresses (also referred to as virtualIP addresses) as source and destination IP addresses. The overlay IPaddress of the compute instance can, in some embodiments, belong to aCIDR range of the VLAN. The other overlay IP address can belong to theCIDR range (in which case, the L2 frame flows within the VLAN) oroutside the CIDR range (in which case, the L2 frame is destined to orreceived from another network). The L2 frame can also include a VLAN tagthat uniquely identifies the VLAN and that can be used to distinguishagainst multiple L2 VNICs on the same NVD. The L2 frame can be receivedin an encapsulated packet by the NVD via a tunnel from the host machineof the compute instance, from another NVD, or from the server fleethosting the VSRS. In these different cases, the encapsulated packet canbe an L3 packet sent on the physical network, where the source anddestination IP addresses are physical IP addresses. Different types ofencapsulation are possible, including GENEVE encapsulation. The NVD candecapsulate the received packet to extract the L2 frame. Similarly, tosend an L2 frame, the NVD can encapsulate it in an L3 packet and send iton the physical substrate.

For intra-VLAN egress traffic from the instance 2 1000-B, NVD 2 1001-Breceives a frame from the host machine of instance 2 1000-B over anEthernet link. The frame includes an interface identifier thatidentifies L2 VNIC 2 1000-B. The frame includes the overlay MAC addressof instance 2 1000-B (e.g., M.2) as the source MAC address and theoverlay MAC address of instance 1 1000-A (e.g., M.1) as the destinationMAC address. Given the interface identifier, NVD 2 1001-B passes theframe to L2 VNIC 2 1002-B for further processing. L2 VNIC 2 1002-Bforwards the frame to L2 switch 2 1004-B. Based on L2 forwarding table1006-B, L2 switch 2 1004-B determines whether the destination MACaddress is known (e.g., matches with an entry in L2 forwarding table1006-B,).

If known, the L2 switch 2 1004-B determines that the L2 VNIC 1 1002-A isthe relevant tunnel endpoint and forwards the frame to the L2 VNIC 11002-A. The forwarding can include encapsulation of the frame in apacket and decapsulation of the packet (e.g., GENEVE encapsulation anddecapsulation), where the packet includes the frame, the physical IPaddress of NVD 1 1001-A (e.g., IP.1) as the destination address, and thephysical IP address of the NVD 2 1001-B (e.g., IP.2) as the sourceaddress.

If unknown, the L2 switch 2 1004-B broadcasts the frame to the variousVNICs of the VLAN (e.g., including the L2 VNIC 1 1002-A and any other L2VNIC of the VLAN), where the broadcasted frames are processed (e.g.,encapsulated, sent, decaspulated) between the relevant NVDs. In someembodiments, this broadcast can be performed, or more specifically,emulated, at the physical network, encapsulating the frame separately toeach L2 VNIC, including the VSRS in the VLAN. Thus, the broadcast isemulated via a series of replicated unicast packets at the physicalnetwork. In turn, each L2 VNIC receives the frame and learns theassociation between the interface identifier of the L2 VNIC 2 1002-B andthe source MAC address (e.g., M.2) and the source physical IP address(e.g., IP.2).

For intra-VLAN ingress traffic to compute instance 2 1000-B from computeinstance 1 1000-A, NVD 2 1001-B receives a packet from NVD 1. The packethas IP.1 as the source address and a frame, where the frame includes M.2as the destination MAC address and M.1 as the source MAC address. Theframe also includes the network identifier of L2 VNIC 1 1002-A. Upondecapsulation, VNIC 2 receives the frame and learns that this interfaceidentifier is associated with M.1 and/or with IP.1 and stores, ifpreviously unknown, this learned information in L2 forwarding table1006-B, at switch 2, for subsequent egress traffic. Alternatively, upondecapsulation, the L2 VNIC 2 1002-B receives the frame and learns thatthis interface identifier is associated with M.1 and/or with IP.1 andrefreshes the expiration time if this information is already known.

For egress traffic sent from instance 2 1000-B in the VLAN 1000 to aninstance in another VLAN, a similar flow as the above egress traffic canexist, except that the VSRS VNIC and VSRS switch are used. Inparticular, the destination MAC address is not within the L2 broadcastof the VLAN 1000 (it is within the other L2 VLAN). Accordingly, theoverlay destination IP address (e.g., IP.A) of the destination instanceis used for this egress traffic. For example, L2 VNIC 2 1002-Bdetermines that IP.A is outside of the CIDR range of the VLAN 1000.Accordingly, L2 VNIC 2 1002-B sets a destination MAC address to adefault gateway MAC address (e.g., M.DG). Based on M.DG, the L2 switch 21004-B sends the egress traffic to the VSRS VNIC (e.g., via a tunnel,with the proper end-to-end encapsulation). The VSRS VNIC forwards theegress traffic to the VSRS switch. In turn, the VSRS switch performs arouting function, where, based on the overlay destination IP address(e.g., IP.A), the VSRS switch of the VLAN 1000 sends the egress trafficto the VSRS switch of the other VLAN (e.g., via the virtual routerbetween these two VLANs, also with the proper end-to-end encapsulation).Next, the VSRS switch of the other VLAN performs a switching function bydetermining that IP.A is within the CIDR range of this VLAN and performsa look-up of its ARP cache based on IP.A to determine the destinationMAC address associated with IP.A. If no match exists in the ARP cache,ARP requests are sent to the different L2 VNICs of the other VLAN todetermine the destination MAC address. Otherwise, the VSRS switch sendsthe egress traffic to the relevant VNIC (e.g., via a tunnel, with theproper encapsulation).

For ingress traffic to an instance in the VLAN 1000 from an instance inanother VLAN, the traffic flow is similar to the above, except in theopposite direction. For egress traffic from an instance in the VLAN 1000to an L3 network, the traffic flow is similar to the above except thatthe VSRS switch of the VLAN 1000 routes the packet directly to thedestination VNIC in the virtual L3 network via the virtual router (e.g.,without having to route the packet through another VSRS switch). Foringress traffic to an instance in the VLAN 1000 from a virtual L3network, the traffic flow is similar to the above except that the packetis received by the VSRS switch of the VLAN 1000 A that sends it withinthe VLAN as a frame. For traffic (egress or ingress) between the VLAN1000 and other networks, the VSRS switch is similarly used, where itsrouting function is used on the egress to send a packet via the propergateway (e.g., IGW, NGW, DRG, SGW, LPG), and where its switchingfunction is used on the ingress to send a frame within the VLAN 1000.

With reference now to FIG. 11 , a schematic illustration of anembodiment of a VLAN 1100 (e.g., a cloud-based Virtual L2 network) isshown, and specifically an implementation view of the VLAN is shown.

As described herein above, the VLAN can include “n” compute instances1102-A, 1102-B, 1102-N, each of which executes on a host machine. Aspreviously discussed, there can be a one-to-one association between acompute instance and a host machine, or a many-to-one associationbetween a plurality of compute instances and a single host machine. Eachcompute instance 1102-A, 1102-B, 1102-N can be an L2 compute instance,in which case, it is associated with at least one virtual interface(e.g., an L2 VNIC) 1104-A, 1104-B, 1104-N and a switch 1106-A, 1106-B,1106-N. The switches 1106-A, 1106-B, 1106-N are L2 virtual switches andtogether form an L2 distributed switch 1107.

The pair of L2 VNIC 1104-A, 1104-B, 1104-N and switch 1106-A, 1106-B,1106-N associated with a compute instance 1102-A, 1102-B, 1102-N on ahost machine is a pair of software modules on a NVD 1108-A, 1108-B,1108-N connected to the host machine. Each L2 VNIC 1104-A, 1104-B,1104-N represents an L2 port of the customer's perceived single switch(referred to herein as vswitch). Generally, a host machine “i” executesa compute instance “i” and is connected to an NVD “i”. In turn, the NVD“i” executes an L2 VNIC “i” and a “switch “i”. The L2 VNIC “i”represents an L2 port “i” of the vswitch. “i” is a positive integerbetween 1 and “n”. Here also, although one-to-one associations aredescribed, other types of associations are possible. For instance, asingle NVD can be connected to multiple hosts, each executing one ormore compute instances that belong to the VLAN. If so, the NVD hostsmultiple pairs of L2 VNIC and switch, each corresponding to one of thecompute instances.

The VLAN can include an instance of a VSRS 1110. The VSRS 1110 performsswitching and routing functionalities and includes an VSRS VNIC 1112 andan instance of a VSRS switch 1114. The VSRS VNIC 1112 represents a porton the vswitch, where this port connects the vswitch to other networksvia a virtual router. As shown, the VSRS 1110 can be instantiated on aserver fleet 1116.

A control plane 1118 can track information identifying L2 VNICs 1104-A,1104-B, 1104-N and their placements in the VLAN. The control plane 1110can further provide this information to the L2 interfaces 1104-A,1104-B, 1104-N in the VLAN.

As shown in FIG. 11 , the VLAN can be a cloud-based virtual L2 networkthat can be built on top of the physical network 1120. In someembodiments, this physical network 1120 can include the NVDs 1108-A,1108-B, 1108-N.

Generally, a first L2 compute instance of the VLAN (e.g., computeinstance 1 1102-A) can communicate with a second compute instance of theVLAN (e.g., compute instance 2 1102-B) using L2 protocols. For instance,a frame can be sent between these two L2 compute instances over theVLAN. Nonetheless, the frame can be encapsulated, tunneled, routed,and/or subject to other processing such that the frame can sent over theunderlying physical network 1120.

For example, the compute instance 1 1102-A sends a frame destined to thecompute instance 2 1102-B. Depending on the network connections betweenhost machine 1 and NVD 1, NVD1 and the physical network 1120, thephysical network 1120 NVD 2, and NVD 2 and host machine 2 (e.g., TCP/IPconnections, Ethernet connections, tunneling connections, etc.),different types of processing can be applied to the frame. For instance,the frame is received by NVD 1 and encapsulated, and so on and so forth,until the frame reaches the compute instance 2. This processing suchthat the frame can be sent between the underlying physical resources isassumed and, for the purpose of brevity and clarity, its description isomitted from the description the VLAN and the related L2 operations.

Virtual L2 Network Communication

Multiple forms of communication can occur within or with a virtual L2network. These can include intra-VLAN communications. In such anembodiments, a source compute instance can send a communication to adestination compute instance that is in the same VLAN as the sourcecompute instance (CI). The communication can be also sent to an endpointoutside of the VLAN of the source CI. This can include, for example, acommunication between a source CI in a first VLAN to a destination CI ina second VLAN, a communication between a source CI in a first VLAN to adestination CI in a L3 subnet, and/or a communication from a source CIin a first VLAN to a destination CI outside of the VCN containing theVLAN of the source CI. This communication can further include, forexample, receiving a communication at a destination CI from a source CIoutside of the VLAN of the destination CI. This source CI can be inanother VLAN, in a L3 subnet, or outside of the VCN containing the VLANof the source CI.

Each CI within a VLAN can play an active role in the traffic flow. Thisincludes learning interface identifier-to-MAC address, also referred toherein as interface-to-MAC address, mapping of instances within the VLANto maintain L2 forwarding tables within the VLAN, and the sending and/orreceiving of communications (e.g. frames in case of L2 communications).The VSRS can play an active role in communication within the VLAN and incommunication with source or destination CIs outside of the VLAN. TheVSRS can maintain a presence in the L2 network and in the L3 network toenable the egress and ingress communication.

With reference now to FIG. 12 , a flowchart illustrating one embodimentof a process 1200 for intra-VLAN communication is shown. In someembodiments, the process 1200 can be performed by the compute instanceswithin a common VLAN. The process can be specifically performed in theevent that a source CI sends a communication to a destination CI withinthe VLAN, but does not know the IP-to-MAC address mapping of thatdestination CI. This can occur, for example, when a source CI sends apacket to a destination CI having an IP address in the VLAN, but thesource CI does not know the MAC address for that IP address. In thiscase, an ARP process can be performed to learn the destination MACaddress and the IP-to-MAC address mapping.

In the event that the source CI knows the IP-to-MAC address mapping, thesource CI can send the packet directly to the destination CI, and theARP process need not be performed. In some embodiments, this packet canbe intercepted by the source VNIC, which source VNIC in intra-VLANcommunication is an L2 VNIC. If the source VNIC knows theinterface-to-MAC address mapping for the destination MAC address, thenthe source VNIC can encapsulate the packet, for example in an L2encapsulation, and can forward the corresponding frame to thedestination VNIC, which destination VNIC in intra-VLAN communication isan L2 VNIC, for the destination MAC address.

If the source VNIC does not know the interface-to-MAC address mappingfor the MAC address, then the source VNIC can perform an aspect of aninterface-to-MAC address learning process. This can include the sourceVNIC sending the frame to all interfaces within the VLAN. In someembodiments, this frame can be sent via broadcast to all of theinterfaces within the VLAN. In some embodiments, this broadcast can beimplemented at the physical network in the form of serial unicast. Thisframe can include the destination MAC and IP addresses, the interfaceidentifier, and the MAC address and IP address of the source VNIC. Eachof the VNICs in the VLAN can receive this frame and can learn theinterface-to-MAC address mapping of the source VNIC.

Each of the receiving VNICs can further decapsulate the frame andforward the decapsulated frame (e.g., corresponding packet) to theirassociated CI. Each CI can include a network interface which canevaluate the forwarded packet. If the network interface determines thatthe CI having received the forwarded packet does not match thedestination MAC and/or IP address, then the packet is dropped. If thenetwork interface determines that the CI having received the forwardedframe matches the destination MAC and/or IP address, then the packet isreceived by the CI. In some embodiments, the CI having a MAC and/or IPaddress matching the destination MAC and/or IP address of the packet cansend a response to the source CI, whereby the source VNIC can learn theinterface-to-MAC address mapping of the destination CI, and whereby thesource CI can learn the IP-to-MAC address mapping of the destination CI.

When the source CI does not know the IP-to-MAC address mapping, or whenthe source CI's IP-to-MAC address mapping for the destination CI isstale, then the process 1200 can be performed. Thus, when the IP-to-MACaddress mapping is known, then the source CI can send the packet. Whenthe IP-to-MAC address mapping is not known, then the process 1200 can beperformed. When the interface-to-MAC address mapping is not known, theinterface-to-MAC address learning process outlined above can beperformed. When the interface-to-MAC address mapping is known, then thesource VNIC can send the corresponding frame to the destination VNIC.The process 1200 begins at block 1202, wherein the source CI determinesthat the IP-to-MAC address mapping of the destination CI is unknown tothe source CI. In some embodiments, this can include the source CIdetermining a destination IP address for a packet, and determining thatthe destination IP address is not associated with a MAC address storedin a mapping table of the source CI. Alternatively, the source CI candetermine that the IP-to-MAC address mapping for the destination CI isstale. A mapping can be stale, in some embodiments, if the mapping hasnot been updated and/or verified within some time limit. Upondetermining that the IP-to-MAC address mapping of the destination CI isunknown and/or stale to the source CI, the source CI initiates an ARPrequest for the destination IP address and sends the ARP request forEthernet broadcast.

At block 1204, the source VNIC, also referred to herein as the sourceinterface, receives the ARP request from the source CI. The sourceinterface identifies all interfaces on the VLAN, and sends the ARPrequest to all interfaces on the VLAN broadcast domain. As previouslymentioned, as the control plane knows all of the interfaces on the VLANand provides that information to the interfaces with the VLAN, thesource interface likewise knows all of the interfaces in the VLAN and isable to send the ARP request to each of the interfaces in the VLAN. Todo this, the source interface replicates the ARP request andencapsulates one of the ARP requests for each of the interfaces on theVLAN. Each encapsulated ARP request includes the source CI interfaceidentifier and source CI MAC and IP addresses, the target IP address,and the destination CI interface identifier. The source CI interfacereplicates an Ethernet broadcast by sending the replicated andencapsulated ARP requests (e.g., ARP messages) as serial unicast, onesent to each interface in the VLAN.

At block 1206, each interface in the VLAN broadcast domain receives anddecapsulates an ARP messages. Each of the interfaces in the VLANbroadcast domain that receives the ARP message learns theinterface-to-MAC address mapping of the source VNIC of the source CI(e.g., interface identifier of the source interface to MAC address ofthe source CI) as this message identifies the source CI MAC and IPaddresses and the source CI interface identifier. As part of learningthe interface-to-MAC address mapping for the source CI, each of theinterfaces can update its mapping table (e.g., its L2 forwarding table),and can provide the updated mapping to its associated switch and/or CI.Each recipient interface, except the VSRS, can forward a decapsulatedpacket to their associated CI. The CI recipient of the forwardeddecapsulated packet, and specifically the network interface of that CI,can determine if the target IP address matches the IP address of the CI.If the IP address of the CI associated with that interface does notmatch the destination CI IP address, then, in some embodiments, thepacket is dropped by that CI, and no further action is taken. In thecase of the VSRS, the VSRS can determine if the target IP addressmatches the IP address of the VSRS. If the IP address of the VSRS doesnot match the target IP address specified in the received packet, then,in some embodiments, the packet is dropped by the VSRS and no furtheraction is taken.

If it is determined that the destination CI IP address specified in thereceived packet matches the IP address of the CI associated with therecipient interface (destination CI), then, and as indicated in block1208, the destination CI sends a response, which can be a unicast ARPresponse to the source interface. This response includes the destinationCI MAC address and destination CI IP address, and the source CI IP andMAC addresses. This response is received by the destination interfacewhich encapsulates the unicast ARP response as indicated in block 1210.In some embodiments, this encapsulation can comprise GENEVEencapsulation. The destination interface can forward the encapsulatedARP response via the destination switch to the source interface. Thisresponse includes the destination CI MAC and IP addresses anddestination CI interface identifier, and the source CI MAC and IPaddresses and the source CI interface identifier.

At block 1212, the source interface receives and decapsulates the ARPresponse. The source interface can further learn the interface-to-MACaddress mapping for the destination CI based on information contained inthe encapsulation and/or in the encapsulated frame. The source interfacecan, in some embodiments, forward the ARP response to the source CI.

At block 1214, the source CI receives the ARP response. In someembodiments, the source CI can update a mapping table based oninformation contained in the ARP response, and specifically update amapping table to reflect the IP-to-MAC address mapping based on the MACand IP addresses of the destination CI. Subsequently, the source CI canthen send a packet to the destination CI based on this MAC address. Thispacket can include the MAC address and interface identifier of thesource CI as the source MAC address and source interface and the MACaddress and interface identifier of the destination CI as thedestination MAC address and destination interface.

At block 1216, the source interface can receive the packet from thesource CI. The source interface can encapsulate the packet, and in someembodiments, this encapsulation uses a GENEVE encapsulation. The sourceinterface can forward the corresponding frame to the destination CI, andspecifically to the destination interface. The encapsulated frame caninclude the MAC address and interface identifier of the source CI as thesource MAC address and source interface identifier and the MAC addressand interface identifier of the destination CI as the destination MACaddress and destination interface.

At block 1218, the destination interface receives the frame form thesource interface. The destination interface can decapsulate the frame,and then can forward the corresponding packet to the destination CI. Atblock 1220, the destination CI receives the packet from the destinationinterface.

IGMP

In an L2 physical network, a frame can be multicasted to a group ofdevices that are associated with a group MAC address. To do so, a switchof this network sends IGMP queries to the different devices of thenetwork requesting whether they should be added to a multicast groupthat has the group MAC address. If an IGMP response of a deviceindicates that the device should be a member of the multicast group, theswitch associates the device's MAC address with the group MAC address inan IGMP table. Thereafter, upon receiving a frame destined to the groupMAC address, the switch replicates the frame into multiple frames, eachof which is destined to a MAC address of a device of the multicastgroup, and sends the replicates frames to the relevant devices.

In comparison, and as described herein, a Layer 2 virtual network doesnot include a single switch. Instead, a distributed switch isimplemented (referred to herein as a vswitch or an L2 vswitch) andincludes a plurality of L2 VNICs and L2 virtual switches that are hostedon one or more NVDs. As such, no single, centralized switch may exist tosend an IGMP query to different compute instances of the Layer 2 virtualnetwork. Instead, the IGMP querying needs to be distributed across theL2 virtual switches. Furthermore, the IGMP responses are not received bya single, centralized switch. Instead, each L2 virtual switch mayreceive an IGMP response from a corresponding compute instance. An IGMPtable needs to be generated from the responses received by the pluralityof L2 virtual switches collect and distributed thereto to enable groupmulticasting.

FIG. 13 illustrates an example environment suitable to define a Layer 2virtual network configuration. In embodiments, the environment includesa computer system 1310 in communication with a customer device 1320 overone or more networks (not shown). The computer system 1310 can include aset of hardware computing resources that host a VCN 1312. A controlplane hosted by one or more of the hardware computing resources canreceive and process input from the customer device 1320 to deploy an L2virtual network (shown as an L2 VLAN 1314 in FIG. 13 ) within the VCN1312.

In an example, the input from the customer device 1320 can includevarious types of information. This information can be specified via aconsole or API calls and can include an L2 VLAN configuration 1322,among other customer-specified configurations.

The L2 VLAN configuration 1322 can indicate, for instance, the number,type(s), and configuration(s) of L2 compute instances to be included inthe L2 VLAN 1314. In addition, the L2 VLAN configuration 1322 canindicate customer-specified names of ports on the customer-perceivedvswitch, MAC addresses of compute instances (which can be L2 computeinstances), and the associations between the ports and the MAC addresses(or, more generally, the compute instances). For instance, the customercan specify that the L2 VLAN 1314 needs to include two L2 computeinstances, the first one having a MAC address M.1 and associated with afirst port named P1, the first one having a MAC address M.2 andassociated with a second port named P2.

The control plane receives the various information to then deploy andmanage the different resources of the L2 VLAN 1314. For instance, the L2VLAN 1314 is configured according to the L2 VLAN configuration 1322, andincludes the requested compute instances hosted on host machines, and L2VNIC-L2 virtual switch pairs hosted on NVDs. The control plane can alsomaintain a mapping between the customer-specified L2 VLAN configuration1322 and the actual topology of the L2 VLAN 1314. For instance, themapping indicates that an L2 VNIC emulates a port of the vswitch and canassociate the L2 VNIC (e.g., its interface identifier, its MAC address(if not specified), and/or the IP address of the NVD hosting the L2VNIC) with the port's name (and with the specified MAC address ifspecified). The mapping can also associate the L2 VNIC and theassociated L2 virtual switch with the relevant compute instance andindicates the NVD that hosts the L2 VNIC and L2 virtual switch and thehost machine that hosts the compute instance.

FIG. 14 illustrates an example IGMP technique in a Layer 2 virtualnetwork. The Layer 2 virtual network is referred to herein as a VLAN.The top portion of FIG. 14 illustrates an implementation view 1410 ofthe VLAN. The bottom portion of FIG. 14 illustrates a customerpresentation 1420 of the VLAN. The customer presentation 1420 gives aperception to a customer for which the Layer 2 virtual network isdeployed that the L2 vswitch of this network is an IGMP-enabled port.The implementation view 1410 indicates how the IGMP techniques can beimplemented, where a port of the L2 vswitch is emulated by an L2 VNICand this L2 VNIC along with the associated L2 virtual switch can supportthe IGMP functionalities.

In an example, and as described herein above, an L2 VNIC of an NVDlearns interface-to-MAC address mapping based on the ingress traffic.Such a mapping can be sent to a control plane (e.g., the control plane,or more generally, a computer system of the VCN that includes the VLAN),along with an identifier of the VLAN. The control plane can receivesimilar mappings from the different NVDs hosting different L2 VNICs andgenerate a mapping(s) between interface identifiers, MAC addresses,physical IP addresses (e.g., of NVDs), and VLAN identifiers, among otherthings.

For example, VNIC 1 learns that M.2 (the overlay MAC address of computeinstance 2) is associated with ID.2 (the interface identifier of L2 VNIC2) and with IP.2 (the physical address of NVD 2), and that M.n (theoverlay MAC address of compute instance n) is associated with ID.n (theinterface identifier of L2 VNIC n) and with IP.n (the physical addressof NVD n). Similarly, VNIC 2 learns that M.1 (the overlay MAC address ofcompute instance 1) is associated with ID.1 (the interface identifier ofL2 VNIC 1) and with IP.1 (the physical address of NVD 1). Theseassociations are reported as part of the mappings to the control planethat, in turn, can generate a mapping of: {customer 1; M.1→ID.1, IP.1;VLAN A}, {customer 1, M.2→ID.2, IP.2; VLAN A}, . . . , {customer 1,M.n→ID.n, IP.n; VLAN A}.

Further, the control plan can generate and maintain a mapping betweencustomer-specified port names and a distribution of resources of theVLAN on the physical network. For example, this mapping indicates thatport “i” is configured for compute instance “i” and corresponds to L2VNIC “i,” which, in turn, is associated with L2 virtual switch “i,” andthis pair is hosted by NVD “i.” This mapping can be expressed as{customer 1; CI.1→P.1; P.1→M.1; M.1→ID.1, SW.1, IP.1; VLAN A}, wherein“CI.1” identifies compute instance 1 (using the nomenclature defined bythe customer), P.1 identifies port 1 (using the nomenclature defined bythe customer), M.1 identifies the MAC address associated with computeinstance 1, ID.1 identifies the L2 VNIC 1, SW.1 identifies the L2virtual switch 1, IP.1 identifies the IP address of NVD 1, and VLAN Aidentifies the VLAN.

As such, the control plane maintains a customer-defined configuration ofthe VLAN (e.g., compute instance 1 is connected to port 1, etc.), amapping of the VLAN to the actual network implementation on the physicalnetwork, and a mapping that associates the customer-definedconfiguration and the actual implementation. Such information can enablethe control plane to orchestrate IGMP functionalities in the VLAN.

For example, based on the mappings, the control plane determines theNVDs that host L2 virtual switches associated with the compute instancesof the VLAN (e.g., NVD 1, NVD 2, . . . , NVD n). The control plane sendsa request to each of these NVDs for periodic IGMP queries within theVLAN (e.g., NVD 1, NVD 2, . . . , NVD n). The periodic time interval canbe thirty seconds or some other predefined value. An NVD (e.g., NVD 1)receives the request and determines the applicable L2 VNIC(s) (e.g. L2VNIC 1). Next, an L2 VNIC (e.g., L2 VNIC 1) sends an IGMP query to theassociated compute instance (e.g., compute instance 1) to determinewhether the compute instance should be added to a multicast group (orremoved from the multicast group if previously added). Upon the IGMPresponse of the compute instance for addition (or for removal), the L2VNIC updates the associated L2 virtual switch (e.g., L2 virtual switch1), such that the L2 virtual switch can update its local IGMPconfiguration (e.g., for addition, including an association between theoverlay MAC address of the compute instance and a group MAC address ofthe multicast group (e.g., “M.G”) in its local IGMP table; for removal,deleting this association from the local IGMP table). The responses ofthe different compute instances (or the updates to the local IGMPtables) are also reported to the control plane that then updates themapping to include the IGMP configuration (e.g., {customer 1, M.1→ID.1,IP.1; VLAN A, M.G listener: yes}, {customer 1 M.2→ID.2, IP.2; VLAN A,listener: no}, . . . , {customer 1, M.n→ID.n, IP.n; VLAN A, M.Glistener: yes} indicating that compute instances 1 and n are members ofthe multicast group, but compute instance 2 is not). The control planecan send the entire or portions of collected IGMP configuration (e.g.,an IGMP table taking the form of: {M.1, M.G, listener: yes}, {M.2, M.G,listener: no}, . . . , { M.n, M.G, listener: yes}) to the NVDs. In turn,the NVDs update their local L2 virtual switches with the relevantportions of the received IGMP configuration for use in subsequent framemulticasting.

The multicasting can be performed by the NVDs based on the locallystored IGMP tables. For instance, NVD 1 receives a frame of computeinstance 1, where this frame includes the multicast MAC address (e.g.,M.G) as a destination MAC address. Based on its local IGMP table 1, L2virtual switch 1 determines that M.n (the MAC address of computeinstance n) and M.3 (the MAC address of a compute instance 3, not shownin FIG. 14 ) are associated with M.G. Accordingly, L2 virtual switch 1replicates the frame twice, resulting in a first frame having M.n as thedestination MAC address and a second frame having M.3 as the destinationMAC address. These replicated frames are sent to L2 VNIC n and L2 VNIC 3(L2 VNIC 3 corresponds to the third compute instance 3 and is not shownin FIG. 14 ).

As further described herein above, an NVD hosting a VSRS VNIC and a VSRSswitch can be used for communication between the VLAN and a resourceoutside of the VLAN. The IGMP configuration collected by the controlplane can be sent to this NVD. Hence, when a speaker to the multicastgroup is outside of the VLAN, the VSRS VNIC can receive the associatedtraffic. Based on it switching function, the VSRS switch determines thecompute instances of the VLAN associated with the multicast group andsends multicast frames to the Layer 2 VNICs associated with thesecompute instances.

FIG. 15 is a flowchart illustrating a process for generating an IGMPtable in a Layer 2 virtual network. In some embodiments, the process1500 can be performed by a control plane, or another VCN system, thatmanages the deployment of the Layer 2 virtual network on an underlyingphysical network. In the interest of clarity, the process 1500 isdescribed in connection with two NVDs, each hosting a pair of L2 VNICand L2 virtual switch for a different compute instance. However, theprocess similarly applies when a different number of NVDs, L2 VNIC-L2virtual switch pairs, and/or compute instances exist.

The process 1500 begins at block 1502, where the control plane receives,from a first NVD, first information about an IGMP response of a firstcompute instance of an L2 virtual network. In some embodiments, thefirst information indicates that the first compute instance is to beadded to a multicast group. This compute instance can be hosted on ahost machine that is communicatively coupled with the first NVD. Thefirst NVD can host a first L2 VNIC and a first L2 virtual switchassociated with the first compute instance. In some embodiments, thecontrol plane can send a request to the first NVD to perform an IGMPquery. The first information is received from the first NVD in aresponse to the request. In such embodiments, the control plane candetermine, based on mapping information, that the first NVD hosts thefirst L2 VNIC and the first L2 virtual switch that are associated withthe compute instance of the L2 virtual network and can send the requestbased on this determination.

At block 1504, the control plane receives, from a second NVD, secondinformation about an IGMP response of a second compute instance of theL2 virtual network. In some embodiments, the second information alsoindicates that the second compute instance is to be added to themulticast group. This compute instance can be hosted on the same ordifferent host machine that is communicatively coupled with the secondNVD. The second NVD can host a second L2 VNIC and a second L2 virtualswitch associated with the second compute instance. Although the process1500 is described in connection with two different NVDs, this processalso applies when a single NVD hosts multiple L2 VNIC and L2 virtualswitch pairs. In some embodiments, the control plane can send a requestto the second NVD to perform an IGMP query. The second information isreceived from the second NVD in a response to the request. In suchembodiments, the control plane can determine, based on mappinginformation, that the second NVD hosts the second L2 VNIC and the secondL2 virtual switch that are associated with the second compute instanceof the L2 virtual network and can send the request based on thisdetermination. The requests at blocks 1502 and 1504 can be sent inparallel or sequentially, using any type of mechanism, such as abroadcast or a unicast.

At block 1506, the control plane generates an IGMP table based on thefirst information and the second information. In some embodiments, theIGMP table associates the MAC address of the first compute instance andthe MAC address of the second compute instance with a group MAC addressof the multicast group and indicates that the two MAC addresses arelisteners. The control plane may have also received informationindicating that another compute instance of the L2 virtual network isnot to be added to (or is to be removed from) the multicast group. Inthis case, the IGMP table does not associate the MAC address with thegroup MAC address or can include an association that the MAC address isnot a listener. The MAC addresses of the compute instances can bedetermined based on mapping information maintained by the control planeabout the customer-defined configuration of the L2 virtual network andthe deployment of the resources of the L2 virtual network on thephysical network. The group MAC address may be generated by the controlplane or defined based on customer input.

At block 1508, the control plane sends at least a first portion of theIGMP table to the first NVD. In some embodiments, the first NVD alreadyhas the first information about the first compute instance beingassociated with the multicast group. As such, the control plane need notsend the entire IGMP table to the first NVD. Instead, the control planemay send the portion of the IGMP table including information that maynot already be available to the first NVD. For example, the portionincludes information about the second compute instance (e.g., theassociation of the second compute instance with the multicast group) andexcludes information about the first compute instance (e.g., theassociation of the first compute instance with the multicast group). Inother embodiments, the entire IGMP table is sent to the first NVD.

At block 1510, the control plane sends at least a second portion of theIGMP table to the second NVD. In some embodiments, the second NVDalready has the second information about the second compute instancebeing associated with the multicast group. As such, the control planeneed not send the entire IGMP table to the second NVD. Instead, thecontrol plane may send the portion of the IGMP table includinginformation that may not already be available to the second NVD. Forexample, the portion includes information about the first computeinstance (e.g., the association of the first compute instance with themulticast group) and excludes information about the second computeinstance (e.g., the association of the second compute instance with themulticast group). In other embodiments, the entire IGMP table is sent tothe second NVD.

FIG. 16 is a flowchart illustrating a process for updating an IGMP tablein a Layer 2 virtual. In some embodiments, the process 1600 can beperformed by a control plane, or another VCN system, that manages thedeployment of the Layer 2 virtual network on an underlying physicalnetwork. In the interest of clarity, the process 1600 is described inconnection with an update from an NVD. However, the process 1600similarly applies to when multiple updates are received from the sameNVD or different NVDs. It is assumed that an IGMP table is alreadygenerated (e.g., based on performing the process 1500).

The process 1600 begins at block 1602, where the control plane receives,from a first NVD, first information indicating an update to a multicastgroup. In some embodiments, the first information indicates that a firstcompute instance is to be removed from the multicast group (if alreadyadded to the multicast group) or to be added to the multicast group (ifnot already added to or previously removed from the multicast group).The first information can be received based on a push mechanism that thefirst NVD implements, or the first information can be received in aresponse to a request from the control plane for the update for an IGMPquery.

At block 1604, the control plane generates an update to the IGMP table.In some embodiments, when the first information indicates that the firstcompute device is to be removed, the control plane updates the IGMPtable by removing, from the IGMP table, the association of the firstcompute instance with the multicast group (e.g., by deleting an entrythat associates the first compute instance's MAC address with the groupMAC address or by indicating that the first compute instance is not alistener to the multicast group). Conversely, when the first informationindicates that the first compute device is to be added, the controlplane updates the IGMP table by adding, to the IGMP table, theassociation of the first compute instance with the multicast group(e.g., by inserting an entry that associates the first computeinstance's MAC address with the group MAC address or by indicating thatthe first compute instance is a listener to the multicast group). Infirst embodiments, at this point, the first NVD may have updated its ownlocal IGMP table to reflect the update to the first compute instance'smembership to the multicast group. Accordingly, the control plane neednot send the update or an updated IGMP table to the first NVD. In suchembodiments, blocks 1606 and 1608 can be performed. In secondembodiments, the control plane may periodically, upon receiving anupdate, or upon receiving a number of updates that exceeds a threshold,send an updated IGMP table and/or the update(s) to all the NVD hostingL2 VNIC and L2 virtual switch pairs of the L2 virtual network.

At block 1606, the control plane determines a set of NVDs to which theupdate is to be sent. As indicated above, the set can include, in thefirst embodiments, one or more NVDs other than the first NVD or, in thesecond embodiments, NVDs that include the first NVD. The control planecan determine the set of NVDs based on mapping information about the L2virtual network. In the first embodiments, the control plane excludesthe first NVD. For a second NVD that hosts a second L2 VNIC and L2virtual switch associated with a second compute instance of the L2virtual network, the control plane can also determine whether the secondcompute instance is a member of the multicast group. If so, the controlplane can determine that the second NVD is to receive the updatebecause, if a frame originates from the second compute instance and isdestined to the group MAC address, this frame may need to no longer bereplicated (if the update removes the first compute instance) or to bereplicated (if the update adds the first compute instance). Otherwise,the control plane can determine that the second NVD need not receive theupdate. In the second embodiments, the first NVD and the second NVDwould be added to the set (e.g., their identifiers included in the set).

At block 1608, the control plane sends the update to the set of NVDs. Insome embodiments, the control plane sends the entire updated IGMP table.In some other embodiments, the control plane sends only the updatedportion of the IGMP table (e.g., the added entry or an indication aboutthe entry that is removed from the IGMP table and that each NVD from theset is to remove from its local IGMP table).

FIG. 17 is a flowchart illustrating a process for performing IGMPquerying in a Layer 2 virtual network. In some embodiments, the process1700 can be performed by an NVD that hosts a first L2 VNIC and a firstL2 virtual switch associated with a first compute instance, where the L2virtual network includes the L2 VNIC, L2 virtual switch, and the firstcompute instance. In the interest of clarity, the process 1700 isdescribed in connection with the NVD hosting a single L2 VNIC-L2 virtualswitch pair. However, the process similarly applies when the NVD hostsmultiple of such pairs. In this case, the NVD can store a local IGMPtable for each L2 virtual switch, or the NVD can store a single localIGMP table and associates entries in this table with the different L2virtual switches.

The process 1700 begins at block 1702, where the NVD receives a requestfor an IGMP query. In some embodiments, the request is receivedperiodically from a control plane of the VCN that includes the L2virtual network (or from another VCN system). Based on mappinginformation stored by the control plane, the request may include anidentifier of the first compute instance and/or of the first L2 VNICthat emulates a port of the first compute instance.

At block 1704, the NVD sends an IGMP query to the first computeinstance. In some embodiments, the NVD identifies the first computeinstance based on the request and the host machine that hosts the firstcompute instance. The NVD can then send the request to the host machineindicating that an IGMP response of the first compute instance isrequested.

At block 1706, the NVD receives an IGMP response of the first computeinstance. In some embodiments, the IGMP response is received as aresponse to the IGMP query and indicates that the first compute instanceis to be added to a multicast group (if not previously added) or to beremoved from the multicast group (if previously added).

At block 1708, the NVD stores first information about the IGMP response.In some embodiments, the first information indicates whether the firstcompute instance is to be added or removed from the multicast group. Foraddition, the NVD (e.g., the first L2 VNIC or the first L2 virtualswitch) can include an association of the first compute instance withthe multicast group and this association can be stored in the local IGMPtable of the first L2 virtual switch (e.g., by inserting an entry thatassociates the first compute instance's MAC address with the group MACaddress or by indicating that the first compute instance is a listenerto the multicast group). For removal, the NVD (e.g., the first L2 VNICor the first L2 virtual switch) can remove the association of the firstcompute instance with the multicast group from the local IGMP table(e.g., the corresponding entry is deleted or the first informationindicating that the first compute instance is not a listener to themulticast group).

At block 1710, the NVD sends the first information to a computer system.In some embodiments, the computer system includes the control plane. Thefirst information indicates the membership status of the first computeinstance in the multicast group.

At block 1712, the NVD receives at least a portion of an IGMP table. Insome embodiments, the NVD receives the entire IGMP table that thecomputer system generates and/or maintains based on the firstinformation. In some embodiments, the NVD receives only a portion ofthis IGMP table, where this portion excludes information about themembership of the first compute instance in the multicast group (as thisinformation may already be known to the NVD and corresponds to the firstinformation) and includes information about a membership(s) of a secondcompute instance(s) in the multicast group. An example of the secondcompute instance includes a compute instance associated with a second L2VNIC and a second L2 virtual switch that are hosted by a second,different NVD instead.

At block 1714, the NVD stores the local IGMP table. In some embodiments,the NVD updates the already stored local IGMP table based on the portionreceived at block 1712. For instance, entries from the received portionare added to the local IGMP table. In some other embodiments, the NVDreceives the entire IGMP table. If so, the NVD can replace the localIGMP with the received IGMP table or can compare both tables and add, tothe local IGMP table, entries that are missing from the local IGMP tableand that are available from the received IGMP table.

FIG. 18 is a flowchart illustrating a process for using an IGMP table ina Layer 2 virtual network. In some embodiments, the process 1800 can beperformed by an NVD that hosts a first L2 VNIC and a first L2 virtualswitch associated with a first compute instance, where the L2 virtualnetwork includes the L2 VNIC, L2 virtual switch, and the first computeinstance. In the interest of clarity, the process 1800 is described inconnection with the NVD hosting a single L2 VNIC-L2 virtual switch pair.However, the process similarly applies when the NVD hosts multiple ofsuch pairs. In this case, the NVD can store a local IGMP table for eachL2 virtual switch, or the NVD can store a single local IGMP table andassociates entries in this table with the different L2 virtual switches.Either way, the IGMP table entries can be looked up to determine whethera frame is to be replicated or not.

The process 1800 begins at block 1802, wherein the NVD receives a framehaving header information. In some embodiments, the frame can bereceived from the first compute instance via the host machine (e.g., theframe is an egress frame being sent from the first compute instance).

At block 1804, the NVD determines whether the frame needs to bereplicated. If the frame is to be replicated, block 1806 follows block1804, Otherwise, block 1810 follows block 1804. In some embodiments, thedetermination involves the header information and the IGMP tableentries. In particular, the NVD parses the header information todetermine the destination MAC address and determines whether thisdestination MAC address matches a group MAC address of a multicast group(e.g., the first L2 VNIC passes the frame to the first L2 virtual switchthat then performs a look up of its IGMP table entries). Assuming thatthe destination MAC address is a group MAC address, the NVD (e.g., thefirst L2 virtual switch) determines that the frame is to be replicated,the MAC address(es) of second compute instance(s) associated with thegroup MAC address, and the number of copies (which is equal to thenumber of determined second compute instance).

At block 1806, the NVD generates a replica of the frame. In someembodiments, the NVD (e.g. the first L2 virtual switch) copies thepayload and alters the header information to include a MAC address of asecond compute instance, instead of the group MAC address, as thedestination. This copying can be repeated as needed depending on thenumber of second compute instances determined at block 1806.

At block 1808, the NVD sends the replica. In some embodiments, thereplicated frame is sent, by the first L2 virtual switch, to a second L2VNIC associated with the second computing instance, where the secondcompute instance has the destination MAC address. This copying can berepeated as needed depending on the number of second compute instancesdetermined at block 1806.

At block 1810, the NVD sends the frame. Here, the frame is originallydestined to a second compute instance instead of the multicast groupbecause the header information includes the MAC address of the secondcompute instance as the destination. As such, in some embodiments, theframe is sent by the first L2 virtual switch to a second L2 VNICassociated with the second compute instance.

C—Example Infrastructure as a Service Architectures

As noted above, infrastructure as a service (IaaS) is one particulartype of cloud computing. IaaS can be configured to provide virtualizedcomputing resources over a public network (e.g., the Internet). In anIaaS model, a cloud computing provider can host the infrastructurecomponents (e.g., servers, storage devices, network nodes (e.g.,hardware), deployment software, platform virtualization (e.g., ahypervisor layer), or the like). In some cases, an IaaS provider mayalso supply a variety of services to accompany those infrastructurecomponents (e.g., billing, monitoring, logging, security, load balancingand clustering, etc.). Thus, as these services may be policy-driven,IaaS users may be able to implement policies to drive load balancing tomaintain application availability and performance.

In some instances, IaaS customers may access resources and servicesthrough a wide area network (WAN), such as the Internet, and can use thecloud provider's services to install the remaining elements of anapplication stack. For example, the user can log in to the IaaS platformto create virtual machines (VMs), install operating systems (OSs) oneach VM, deploy middleware such as databases, create storage buckets forworkloads and backups, and even install enterprise software into thatVM. Customers can then use the provider's services to perform variousfunctions, including balancing network traffic, troubleshootingapplication issues, monitoring performance, managing disaster recovery,etc.

In most cases, a cloud computing model will require the participation ofa cloud provider. The cloud provider may, but need not be, a third-partyservice that specializes in providing (e.g., offering, renting, selling)IaaS. An entity might also opt to deploy a private cloud, becoming itsown provider of infrastructure services.

In some examples, IaaS deployment is the process of putting a newapplication, or a new version of an application, onto a preparedapplication server or the like. It may also include the process ofpreparing the server (e.g., installing libraries, daemons, etc.). Thisis often managed by the cloud provider, below the hypervisor layer(e.g., the servers, storage, network hardware, and virtualization).Thus, the customer may be responsible for handling (OS), middleware,and/or application deployment (e.g., on self-service virtual machines(e.g., that can be spun up on demand) or the like.

In some examples, IaaS provisioning may refer to acquiring computers orvirtual hosts for use, and even installing needed libraries or serviceson them. In most cases, deployment does not include provisioning, andthe provisioning may need to be performed first.

In some cases, there are two different challenges for IaaS provisioning.First, there is the initial challenge of provisioning the initial set ofinfrastructure before anything is running. Second, there is thechallenge of evolving the existing infrastructure (e.g., adding newservices, changing services, removing services, etc.) once everythinghas been provisioned. In some cases, these two challenges may beaddressed by enabling the configuration of the infrastructure to bedefined declaratively. In other words, the infrastructure (e.g., whatcomponents are needed and how they interact) can be defined by one ormore configuration files. Thus, the overall topology of theinfrastructure (e.g., what resources depend on which, and how they eachwork together) can be described declaratively. In some instances, oncethe topology is defined, a workflow can be generated that creates and/ormanages the different components described in the configuration files.

In some examples, an infrastructure may have many interconnectedelements. For example, there may be one or more virtual private clouds(VPCs) (e.g., a potentially on-demand pool of configurable and/or sharedcomputing resources), also known as a core network. In some examples,there may also be one or more security group rules provisioned to definehow the security of the network will be set up and one or more virtualmachines (VMs). Other infrastructure elements may also be provisioned,such as a load balancer, a database, or the like. As more and moreinfrastructure elements are desired and/or added, the infrastructure mayincrementally evolve.

In some instances, continuous deployment techniques may be employed toenable deployment of infrastructure code across various virtualcomputing environments. Additionally, the described techniques canenable infrastructure management within these environments. In someexamples, service teams can write code that is desired to be deployed toone or more, but often many, different production environments (e.g.,across various different geographic locations, sometimes spanning theentire world). However, in some examples, the infrastructure on whichthe code will be deployed must first be set up. In some instances, theprovisioning can be done manually, a provisioning tool may be utilizedto provision the resources, and/or deployment tools may be utilized todeploy the code once the infrastructure is provisioned.

FIG. 19 is a block diagram 1900 illustrating an example pattern of anIaaS architecture, according to at least one embodiment. Serviceoperators 1902 can be communicatively coupled to a secure host tenancy1904 that can include a virtual cloud network (VCN) 1906 and a securehost subnet 1908. In some examples, the service operators 1902 may beusing one or more client computing devices, which may be portablehandheld devices (e.g., an iPhone®, cellular telephone, an iPad®,computing tablet, a personal digital assistant (PDA)) or wearabledevices (e.g., a Google Glass® head-mounted display), running softwaresuch as Microsoft Windows Mobile®, and/or a variety of mobile operatingsystems such as iOS, Windows Phone, Android, BlackBerry 8, Palm OS, andthe like, and be Internet, e-mail, short message service (SMS),Blackberry®, or other communication protocol enabled. Alternatively, theclient computing devices can be general purpose personal computersincluding, by way of example, personal computers and/or laptop computersrunning various versions of Microsoft Windows®, Apple Macintosh®, and/orLinux operating systems. The client computing devices can be workstationcomputers running any of a variety of commercially available UNIX® orUNIX-like operating systems, including without limitation the variety ofGNU/Linux operating systems, such as, for example, Google Chrome OS.Alternatively, or in addition, client computing devices may be any otherelectronic device, such as a thin-client computer, an Internet-enabledgaming system (e.g., a Microsoft Xbox gaming console with or without aKinect® gesture input device), and/or a personal messaging device,capable of communicating over a network that can access the VCN 1906and/or the Internet.

The VCN 1906 can include a local peering gateway (LPG) 1910 that can becommunicatively coupled to a secure shell (SSH) VCN 1912 via an LPG 1910contained in the SSH VCN 1912. The SSH VCN 1912 can include an SSHsubnet 1914, and the SSH VCN 1912 can be communicatively coupled to acontrol plane VCN 1916 via the LPG 1910 contained in the control planeVCN 1916. Also, the SSH VCN 1912 can be communicatively coupled to adata plane VCN 1918 via an LPG 1910. The control plane VCN 1916 and thedata plane VCN 1918 can be contained in a service tenancy 1919 that canbe owned and/or operated by the IaaS provider.

The control plane VCN 1916 can include a control plane demilitarizedzone (DMZ) tier 1920 that acts as a perimeter network (e.g., portions ofa corporate network between the corporate intranet and externalnetworks). The DMZ-based servers may have restricted responsibilitiesand help keep security breaches contained. Additionally, the DMZ tier1920 can include one or more load balancer (LB) subnet(s) 1922, acontrol plane app tier 1924 that can include app subnet(s) 1926, acontrol plane data tier 1928 that can include database (DB) subnet(s)1930 (e.g., frontend DB subnet(s) and/or backend DB subnet(s)). The LBsubnet(s) 1922 contained in the control plane DMZ tier 1920 can becommunicatively coupled to the app subnet(s) 1926 contained in thecontrol plane app tier 1924 and an Internet gateway 1934 that can becontained in the control plane VCN 1916, and the app subnet(s) 1926 canbe communicatively coupled to the DB subnet(s) 1930 contained in thecontrol plane data tier 1928 and a service gateway 1936 and a networkaddress translation (NAT) gateway 1938. The control plane VCN 1916 caninclude the service gateway 1936 and the NAT gateway 1938.

The control plane VCN 1916 can include a data plane mirror app tier 1940that can include app subnet(s) 1926. The app subnet(s) 1926 contained inthe data plane mirror app tier 1940 can include a virtual networkinterface controller (VNIC) 1942 that can execute a compute instance1944. The compute instance 1944 can communicatively couple the appsubnet(s) 1926 of the data plane mirror app tier 1940 to app subnet(s)1926 that can be contained in a data plane app tier 1946.

The data plane VCN 1918 can include the data plane app tier 1946, a dataplane DMZ tier 1948, and a data plane data tier 1950. The data plane DMZtier 1948 can include LB subnet(s) 1922 that can be communicativelycoupled to the app subnet(s) 1926 of the data plane app tier 1946 andthe Internet gateway 1934 of the data plane VCN 1918. The app subnet(s)1926 can be communicatively coupled to the service gateway 1936 of thedata plane VCN 1918 and the NAT gateway 1938 of the data plane VCN 1918.The data plane data tier 1950 can also include the DB subnet(s) 1930that can be communicatively coupled to the app subnet(s) 1926 of thedata plane app tier 1946.

The Internet gateway 1934 of the control plane VCN 1916 and of the dataplane VCN 1918 can be communicatively coupled to a metadata managementservice 1952 that can be communicatively coupled to public Internet1954. Public Internet 1954 can be communicatively coupled to the NATgateway 1938 of the control plane VCN 1916 and of the data plane VCN1918. The service gateway 1936 of the control plane VCN 1916 and of thedata plane VCN 1918 can be communicatively coupled to cloud services1956.

In some examples, the service gateway 1936 of the control plane VCN 1916or of the data plane VCN 1918 can make application programming interface(API) calls to cloud services 1956 without going through public Internet1954. The API calls to cloud services 1956 from the service gateway 1936can be one-way: the service gateway 1936 can make API calls to cloudservices 1956, and cloud services 1956 can send requested data to theservice gateway 1936. However, cloud services 1956 may not initiate APIcalls to the service gateway 1936.

In some examples, the secure host tenancy 1904 can be directly connectedto the service tenancy 1919, which may be otherwise isolated. The securehost subnet 1908 can communicate with the SSH subnet 1914 through an LPG1910 that may enable two-way communication over an otherwise isolatedsystem. Connecting the secure host subnet 1908 to the SSH subnet 1914may give the secure host subnet 1908 access to other entities within theservice tenancy 1919.

The control plane VCN 1916 may allow users of the service tenancy 1919to set up or otherwise provision desired resources. Desired resourcesprovisioned in the control plane VCN 1916 may be deployed or otherwiseused in the data plane VCN 1918. In some examples, the control plane VCN1916 can be isolated from the data plane VCN 1918, and the data planemirror app tier 1940 of the control plane VCN 1916 can communicate withthe data plane app tier 1946 of the data plane VCN 1918 via VNICs 1942that can be contained in the data plane mirror app tier 1940 and thedata plane app tier 1946.

In some examples, users of the system, or customers, can make requests,for example create, read, update, or delete (CRUD) operations, throughpublic Internet 1954 that can communicate the requests to the metadatamanagement service 1952. The metadata management service 1952 cancommunicate the request to the control plane VCN 1916 through theInternet gateway 1934. The request can be received by the LB subnet(s)1922 contained in the control plane DMZ tier 1920. The LB subnet(s) 1922may determine that the request is valid, and in response to thisdetermination, the LB subnet(s) 1922 can transmit the request to appsubnet(s) 1926 contained in the control plane app tier 1924. If therequest is validated and requires a call to public Internet 1954, thecall to public Internet 1954 may be transmitted to the NAT gateway 1938that can make the call to public Internet 1954. Memory that may bedesired to be stored by the request can be stored in the DB subnet(s)1930.

In some examples, the data plane mirror app tier 1940 can facilitatedirect communication between the control plane VCN 1916 and the dataplane VCN 1918. For example, changes, updates, or other suitablemodifications to configuration may be desired to be applied to theresources contained in the data plane VCN 1918. Via a VNIC 1942, thecontrol plane VCN 1916 can directly communicate with, and can therebyexecute the changes, updates, or other suitable modifications toconfiguration to, resources contained in the data plane VCN 1918.

In some embodiments, the control plane VCN 1916 and the data plane VCN1918 can be contained in the service tenancy 1919. In this case, theuser, or the customer, of the system may not own or operate either thecontrol plane VCN 1916 or the data plane VCN 1918. Instead, the IaaSprovider may own or operate the control plane VCN 1916 and the dataplane VCN 1918, both of which may be contained in the service tenancy1919. This embodiment can enable isolation of networks that may preventusers or customers from interacting with other users', or othercustomers', resources. Also, this embodiment may allow users orcustomers of the system to store databases privately without needing torely on public Internet 1954, which may not have a desired level ofsecurity, for storage.

In other embodiments, the LB subnet(s) 1922 contained in the controlplane VCN 1916 can be configured to receive a signal from the servicegateway 1936. In this embodiment, the control plane VCN 1916 and thedata plane VCN 1918 may be configured to be called by a customer of theIaaS provider without calling public Internet 1954. Customers of theIaaS provider may desire this embodiment since database(s) that thecustomers use may be controlled by the IaaS provider and may be storedon the service tenancy 1919, which may be isolated from public Internet1954.

FIG. 20 is a block diagram 2000 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 2002 (e.g., service operators 1902 of FIG. 19 ) can becommunicatively coupled to a secure host tenancy 2004 (e.g., the securehost tenancy 1904 of FIG. 19 ) that can include a virtual cloud network(VCN) 2006 (e.g., the VCN 1906 of FIG. 19 ) and a secure host subnet2008 (e.g., the secure host subnet 1908 of FIG. 19 ). The VCN 2006 caninclude a local peering gateway (LPG) 2010 (e.g., the LPG 1910 of FIG.19 ) that can be communicatively coupled to a secure shell (SSH) VCN2012 (e.g., the SSH VCN 1912 of FIG. 19 ) via an LPG 1910 contained inthe SSH VCN 2012. The SSH VCN 2012 can include an SSH subnet 2014 (e.g.,the SSH subnet 1914 of FIG. 19 ), and the SSH VCN 2012 can becommunicatively coupled to a control plane VCN 2016 (e.g., the controlplane VCN 1916 of FIG. 19 ) via an LPG 2010 contained in the controlplane VCN 2016. The control plane VCN 2016 can be contained in a servicetenancy 2019 (e.g., the service tenancy 1919 of FIG. 19 ), and the dataplane VCN 2018 (e.g., the data plane VCN 1918 of FIG. 19 ) can becontained in a customer tenancy 2021 that may be owned or operated byusers, or customers, of the system.

The control plane VCN 2016 can include a control plane DMZ tier 2020(e.g., the control plane DMZ tier 1920 of FIG. 19 ) that can include LBsubnet(s) 2022 (e.g., LB subnet(s) 1922 of FIG. 19 ), a control planeapp tier 2024 (e.g., the control plane app tier 1924 of FIG. 19 ) thatcan include app subnet(s) 2026 (e.g., app subnet(s) 1926 of FIG. 19 ), acontrol plane data tier 2028 (e.g., the control plane data tier 1928 ofFIG. 19 ) that can include database (DB) subnet(s) 2030 (e.g., similarto DB subnet(s) 1930 of FIG. 19 ). The LB subnet(s) 2022 contained inthe control plane DMZ tier 2020 can be communicatively coupled to theapp subnet(s) 2026 contained in the control plane app tier 2024 and anInternet gateway 2034 (e.g., the Internet gateway 1934 of FIG. 19 ) thatcan be contained in the control plane VCN 2016, and the app subnet(s)2026 can be communicatively coupled to the DB subnet(s) 2030 containedin the control plane data tier 2028 and a service gateway 2036 (e.g.,the service gateway of FIG. 19 ) and a network address translation (NAT)gateway 2038 (e.g., the NAT gateway 1938 of FIG. 19). The control planeVCN 2016 can include the service gateway 2036 and the NAT gateway 2038.

The control plane VCN 2016 can include a data plane mirror app tier 2040(e.g., the data plane mirror app tier 1940 of FIG. 19 ) that can includeapp subnet(s) 2026. The app subnet(s) 2026 contained in the data planemirror app tier 2040 can include a virtual network interface controller(VNIC) 2042 (e.g., the VNIC of 1942) that can execute a compute instance2044 (e.g., similar to the compute instance 1944 of FIG. 19 ). Thecompute instance 2044 can facilitate communication between the appsubnet(s) 2026 of the data plane mirror app tier 2040 and the appsubnet(s) 2026 that can be contained in a data plane app tier 2046(e.g., the data plane app tier 1946 of FIG. 19 ) via the VNIC 2042contained in the data plane mirror app tier 2040 and the VNIC 2042contained in the data plane app tier 2046.

The Internet gateway 2034 contained in the control plane VCN 2016 can becommunicatively coupled to a metadata management service 2052 (e.g., themetadata management service 1952 of FIG. 19 ) that can becommunicatively coupled to public Internet 2054 (e.g., public Internet1954 of FIG. 19 ). Public Internet 2054 can be communicatively coupledto the NAT gateway 2038 contained in the control plane VCN 2016. Theservice gateway 2036 contained in the control plane VCN 2016 can becommunicatively coupled to cloud services 2056 (e.g., cloud services1956 of FIG. 19 ).

In some examples, the data plane VCN 2018 can be contained in thecustomer tenancy 2021. In this case, the IaaS provider may provide thecontrol plane VCN 2016 for each customer, and the IaaS provider may, foreach customer, set up a unique compute instance 2044 that is containedin the service tenancy 2019. Each compute instance 2044 may allowcommunication between the control plane VCN 2016, contained in theservice tenancy 2019, and the data plane VCN 2018 that is contained inthe customer tenancy 2021. The compute instance 2044 may allow resourcesthat are provisioned in the control plane VCN 2016 that is contained inthe service tenancy 2019, to be deployed or otherwise used in the dataplane VCN 2018 that is contained in the customer tenancy 2021.

In other examples, the customer of the IaaS provider may have databasesthat live in the customer tenancy 2021. In this example, the controlplane VCN 2016 can include the data plane mirror app tier 2040 that caninclude app subnet(s) 2026. The data plane mirror app tier 2040 canreside in the data plane VCN 2018, but the data plane mirror app tier2040 may not live in the data plane VCN 2018. That is, the data planemirror app tier 2040 may have access to the customer tenancy 2021, butthe data plane mirror app tier 2040 may not exist in the data plane VCN2018 or be owned or operated by the customer of the IaaS provider. Thedata plane mirror app tier 2040 may be configured to make calls to thedata plane VCN 2018 but may not be configured to make calls to anyentity contained in the control plane VCN 2016. The customer may desireto deploy or otherwise use resources in the data plane VCN 2018 that areprovisioned in the control plane VCN 2016, and the data plane mirror apptier 2040 can facilitate the desired deployment, or other usage ofresources, of the customer.

In some embodiments, the customer of the IaaS provider can apply filtersto the data plane VCN 2018. In this embodiment, the customer candetermine what the data plane VCN 2018 can access, and the customer mayrestrict access to public Internet 2054 from the data plane VCN 2018.The IaaS provider may not be able to apply filters or otherwise controlaccess of the data plane VCN 2018 to any outside networks or databases.Applying filters and controls by the customer onto the data plane VCN2018, contained in the customer tenancy 2021, can help isolate the dataplane VCN 2018 from other customers and from public Internet 2054.

In some embodiments, cloud services 2056 can be called by the servicegateway 2036 to access services that may not exist on public Internet2054, on the control plane VCN 2016, or on the data plane VCN 2018. Theconnection between cloud services 2056 and the control plane VCN 2016 orthe data plane VCN 2018 may not be live or continuous. Cloud services2056 may exist on a different network owned or operated by the IaaSprovider. Cloud services 2056 may be configured to receive calls fromthe service gateway 2036 and may be configured to not receive calls frompublic Internet 2054. Some cloud services 2056 may be isolated fromother cloud services 2056, and the control plane VCN 2016 may beisolated from cloud services 2056 that may not be in the same region asthe control plane VCN 2016. For example, the control plane VCN 2016 maybe located in “Region 1,” and cloud service “Deployment 19” may belocated in Region 1 and in “Region 2.” If a call to Deployment 19 ismade by the service gateway 2036 contained in the control plane VCN 2016located in Region 1, the call may be transmitted to Deployment 19 inRegion 1. In this example, the control plane VCN 2016, or Deployment 19in Region 1, may not be communicatively coupled to, or otherwise incommunication with, Deployment 19 in Region 2.

FIG. 21 is a block diagram 2100 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 2102 (e.g., service operators 1902 of FIG. 19 ) can becommunicatively coupled to a secure host tenancy 2104 (e.g., the securehost tenancy 1904 of FIG. 19 ) that can include a virtual cloud network(VCN) 2106 (e.g., the VCN 1906 of FIG. 19 ) and a secure host subnet2108 (e.g., the secure host subnet 1908 of FIG. 19 ). The VCN 2106 caninclude an LPG 2110 (e.g., the LPG 1910 of FIG. 19 ) that can becommunicatively coupled to an SSH VCN 2112 (e.g., the SSH VCN 1912 ofFIG. 19 ) via an LPG 2110 contained in the SSH VCN 2112. The SSH VCN2112 can include an SSH subnet 2114 (e.g., the SSH subnet 1914 of FIG.19 ), and the SSH VCN 2112 can be communicatively coupled to a controlplane VCN 2116 (e.g., the control plane VCN 1916 of FIG. 19 ) via an LPG2110 contained in the control plane VCN 2116 and to a data plane VCN2118 (e.g., the data plane 1918 of FIG. 19 ) via an LPG 2110 containedin the data plane VCN 2118. The control plane VCN 2116 and the dataplane VCN 2118 can be contained in a service tenancy 2119 (e.g., theservice tenancy 1919 of FIG. 19 ).

The control plane VCN 2116 can include a control plane DMZ tier 2120(e.g., the control plane DMZ tier 1920 of FIG. 19 ) that can includeload balancer (LB) subnet(s) 2122 (e.g., LB subnet(s) 1922 of FIG. 19 ),a control plane app tier 2124 (e.g., the control plane app tier 1924 ofFIG. 19 ) that can include app subnet(s) 2126 (e.g., similar to appsubnet(s) 1926 of FIG. 19 ), and a control plane data tier 2128 (e.g.,the control plane data tier 1928 of FIG. 19 ) that can include DBsubnet(s) 2130. The LB subnet(s) 2122 contained in the control plane DMZtier 2120 can be communicatively coupled to the app subnet(s) 2126contained in the control plane app tier 2124 and to an Internet gateway2134 (e.g., the Internet gateway 1934 of FIG. 19 ) that can be containedin the control plane VCN 2116, and the app subnet(s) 2126 can becommunicatively coupled to the DB subnet(s) 2130 contained in thecontrol plane data tier 2128 and to a service gateway 2136 (e.g., theservice gateway of FIG. 19 ) and a network address translation (NAT)gateway 2138 (e.g., the NAT gateway 1938 of FIG. 19 ). The control planeVCN 2116 can include the service gateway 2136 and the NAT gateway 2138.

The data plane VCN 2118 can include a data plane app tier 2146 (e.g.,the data plane app tier 1946 of FIG. 19 ), a data plane DMZ tier 2148(e.g., the data plane DMZ tier 1948 of FIG. 19 ), and a data plane datatier 2150 (e.g., the data plane data tier 1950 of FIG. 19 ). The dataplane DMZ tier 2148 can include LB subnet(s) 2122 that can becommunicatively coupled to trusted app subnet(s) 2160 and untrusted appsubnet(s) 2162 of the data plane app tier 2146 and the Internet gateway2134 contained in the data plane VCN 2118. The trusted app subnet(s)2160 can be communicatively coupled to the service gateway 2136contained in the data plane VCN 2118, the NAT gateway 2138 contained inthe data plane VCN 2118, and DB subnet(s) 2130 contained in the dataplane data tier 2150. The untrusted app subnet(s) 2162 can becommunicatively coupled to the service gateway 2136 contained in thedata plane VCN 2118 and DB subnet(s) 2130 contained in the data planedata tier 2150. The data plane data tier 2150 can include DB subnet(s)2130 that can be communicatively coupled to the service gateway 2136contained in the data plane VCN 2118.

The untrusted app subnet(s) 2162 can include one or more primary VNICs2164(1)-(N) that can be communicatively coupled to tenant virtualmachines (VMs) 2166(1)-(N). Each tenant VM 2166(1)-(N) can becommunicatively coupled to a respective app subnet 2167(1)-(N) that canbe contained in respective container egress VCNs 2168(1)-(N) that can becontained in respective customer tenancies 2170(1)-(N). Respectivesecondary VNICs 2172(1)-(N) can facilitate communication between theuntrusted app subnet(s) 2162 contained in the data plane VCN 2118 andthe app subnet contained in the container egress VCNs 2168(1)-(N). Eachcontainer egress VCNs 2168(1)-(N) can include a NAT gateway 2138 thatcan be communicatively coupled to public Internet 2154 (e.g., publicInternet 1954 of FIG. 19 ).

The Internet gateway 2134 contained in the control plane VCN 2116 andcontained in the data plane VCN 2118 can be communicatively coupled to ametadata management service 2152 (e.g., the metadata management system1952 of FIG. 19 ) that can be communicatively coupled to public Internet2154. Public Internet 2154 can be communicatively coupled to the NATgateway 2138 contained in the control plane VCN 2116 and contained inthe data plane VCN 2118. The service gateway 2136 contained in thecontrol plane VCN 2116 and contained in the data plane VCN 2118 can becommunicatively coupled to cloud services 2156.

In some embodiments, the data plane VCN 2118 can be integrated withcustomer tenancies 2170. This integration can be useful or desirable forcustomers of the IaaS provider in some cases such as a case in whichsupport may be desired when executing code. The customer may providecode to run that may be destructive, may communicate with other customerresources, or may otherwise cause undesirable effects. In response tothis, the IaaS provider may determine whether to run code given to theIaaS provider by the customer.

In some examples, the customer of the IaaS provider may grant temporarynetwork access to the IaaS provider and request a function to beattached to the data plane tier app 2146. Code to run the function maybe executed in the VMs 2166(1)-(N), and the code may not be configuredto run anywhere else on the data plane VCN 2118. Each VM 2166(1)-(N) maybe connected to one customer tenancy 2170. Respective containers2171(1)-(N) contained in the VMs 2166(1)-(N) may be configured to runthe code. In this case, there can be a dual isolation (e.g., thecontainers 2171(1)-(N) running code, where the containers 2171(1)-(N)may be contained in at least the VMs 2166(1)-(N) that are contained inthe untrusted app subnet(s) 2162), which may help prevent incorrect orotherwise undesirable code from damaging the network of the IaaSprovider or from damaging a network of a different customer. Thecontainers 2171(1)-(N) may be communicatively coupled to the customertenancy 2170 and may be configured to transmit or receive data from thecustomer tenancy 2170. The containers 2171(1)-(N) may not be configuredto transmit or receive data from any other entity in the data plane VCN2118. Upon completion of running the code, the IaaS provider may kill orotherwise dispose of the containers 2171(1)-(N).

In some embodiments, the trusted app subnet(s) 2160 may run code thatmay be owned or operated by the IaaS provider. In this embodiment, thetrusted app subnet(s) 2160 may be communicatively coupled to the DBsubnet(s) 2130 and be configured to execute CRUD operations in the DBsubnet(s) 2130. The untrusted app subnet(s) 2162 may be communicativelycoupled to the DB subnet(s) 2130, but in this embodiment, the untrustedapp subnet(s) may be configured to execute read operations in the DBsubnet(s) 2130. The containers 2171(1)-(N) that can be contained in theVM 2166(1)-(N) of each customer and that may run code from the customermay not be communicatively coupled with the DB subnet(s) 2130.

In other embodiments, the control plane VCN 2116 and the data plane VCN2118 may not be directly communicatively coupled. In this embodiment,there may be no direct communication between the control plane VCN 2116and the data plane VCN 2118. However, communication can occur indirectlythrough at least one method. An LPG 2110 may be established by the IaaSprovider that can facilitate communication between the control plane VCN2116 and the data plane VCN 2118. In another example, the control planeVCN 2116 or the data plane VCN 2118 can make a call to cloud services2156 via the service gateway 2136. For example, a call to cloud services2156 from the control plane VCN 2116 can include a request for a servicethat can communicate with the data plane VCN 2118.

FIG. 22 is a block diagram 2200 illustrating another example pattern ofan IaaS architecture, according to at least one embodiment. Serviceoperators 2202 (e.g., service operators 1902 of FIG. 19 ) can becommunicatively coupled to a secure host tenancy 2204 (e.g., the securehost tenancy 1904 of FIG. 19 ) that can include a virtual cloud network(VCN) 2206 (e.g., the VCN 1906 of FIG. 19 ) and a secure host subnet2208 (e.g., the secure host subnet 1908 of FIG. 19 ). The VCN 2206 caninclude an LPG 2210 (e.g., the LPG 1910 of FIG. 19 ) that can becommunicatively coupled to an SSH VCN 2212 (e.g., the SSH VCN 1912 ofFIG. 19 ) via an LPG 2210 contained in the SSH VCN 2212. The SSH VCN2212 can include an SSH subnet 2214 (e.g., the SSH subnet 1914 of FIG.19 ), and the SSH VCN 2212 can be communicatively coupled to a controlplane VCN 2216 (e.g., the control plane VCN 1916 of FIG. 19 ) via an LPG2210 contained in the control plane VCN 2216 and to a data plane VCN2218 (e.g., the data plane 1918 of FIG. 19 ) via an LPG 2210 containedin the data plane VCN 2218. The control plane VCN 2216 and the dataplane VCN 2218 can be contained in a service tenancy 2219 (e.g., theservice tenancy 1919 of FIG. 19 ).

The control plane VCN 2216 can include a control plane DMZ tier 2220(e.g., the control plane DMZ tier 1920 of FIG. 19 ) that can include LBsubnet(s) 2222 (e.g., LB subnet(s) 1922 of FIG. 19 ), a control planeapp tier 2224 (e.g., the control plane app tier 1924 of FIG. 19 ) thatcan include app subnet(s) 2226 (e.g., app subnet(s) 1926 of FIG. 19 ), acontrol plane data tier 2228 (e.g., the control plane data tier 1928 ofFIG. 19 ) that can include DB subnet(s) 2230 (e.g., DB subnet(s) 2130 ofFIG. 21 ). The LB subnet(s) 2222 contained in the control plane DMZ tier2220 can be communicatively coupled to the app subnet(s) 2226 containedin the control plane app tier 2224 and to an Internet gateway 2234(e.g., the Internet gateway 1934 of FIG. 19 ) that can be contained inthe control plane VCN 2216, and the app subnet(s) 2226 can becommunicatively coupled to the DB subnet(s) 2230 contained in thecontrol plane data tier 2228 and to a service gateway 2236 (e.g., theservice gateway of FIG. 19 ) and a network address translation (NAT)gateway 2238 (e.g., the NAT gateway 1938 of FIG. 19 ). The control planeVCN 2216 can include the service gateway 2236 and the NAT gateway 2238.

The data plane VCN 2218 can include a data plane app tier 2246 (e.g.,the data plane app tier 1946 of FIG. 19 ), a data plane DMZ tier 2248(e.g., the data plane DMZ tier 1948 of FIG. 19 ), and a data plane datatier 2250 (e.g., the data plane data tier 1950 of FIG. 19 ). The dataplane DMZ tier 2248 can include LB subnet(s) 2222 that can becommunicatively coupled to trusted app subnet(s) 2260 (e.g., trusted appsubnet(s) 2160 of FIG. 21 ) and untrusted app subnet(s) 2262 (e.g.,untrusted app subnet(s) 2162 of FIG. 21 ) of the data plane app tier2246 and the Internet gateway 2234 contained in the data plane VCN 2218.The trusted app subnet(s) 2260 can be communicatively coupled to theservice gateway 2236 contained in the data plane VCN 2218, the NATgateway 2238 contained in the data plane VCN 2218, and DB subnet(s) 2230contained in the data plane data tier 2250. The untrusted app subnet(s)2262 can be communicatively coupled to the service gateway 2236contained in the data plane VCN 2218 and DB subnet(s) 2230 contained inthe data plane data tier 2250. The data plane data tier 2250 can includeDB subnet(s) 2230 that can be communicatively coupled to the servicegateway 2236 contained in the data plane VCN 2218.

The untrusted app subnet(s) 2262 can include primary VNICs 2264(1)-(N)that can be communicatively coupled to tenant virtual machines (VMs)2266(1)-(N) residing within the untrusted app subnet(s) 2262. Eachtenant VM 2266(1)-(N) can run code in a respective container2267(1)-(N), and be communicatively coupled to an app subnet 2226 thatcan be contained in a data plane app tier 2246 that can be contained ina container egress VCN 2268. Respective secondary VNICs 2272(1)-(N) canfacilitate communication between the untrusted app subnet(s) 2262contained in the data plane VCN 2218 and the app subnet contained in thecontainer egress VCN 2268. The container egress VCN can include a NATgateway 2238 that can be communicatively coupled to public Internet 2254(e.g., public Internet 1954 of FIG. 19 ).

The Internet gateway 2234 contained in the control plane VCN 2216 andcontained in the data plane VCN 2218 can be communicatively coupled to ametadata management service 2252 (e.g., the metadata management system1952 of FIG. 19 ) that can be communicatively coupled to public Internet2254. Public Internet 2254 can be communicatively coupled to the NATgateway 2238 contained in the control plane VCN 2216 and contained inthe data plane VCN 2218. The service gateway 2236 contained in thecontrol plane VCN 2216 and contained in the data plane VCN 2218 can becommunicatively coupled to cloud services 2256.

In some examples, the pattern illustrated by the architecture of blockdiagram 2200 of FIG. 22 may be considered an exception to the patternillustrated by the architecture of block diagram 2100 of FIG. 21 and maybe desirable for a customer of the IaaS provider if the IaaS providercannot directly communicate with the customer (e.g., a disconnectedregion). The respective containers 2267(1)-(N) that are contained in theVMs 2266(1)-(N) for each customer can be accessed in real-time by thecustomer. The containers 2267(1)-(N) may be configured to make calls torespective secondary VNICs 2272(1)-(N) contained in app subnet(s) 2226of the data plane app tier 2246 that can be contained in the containeregress VCN 2268. The secondary VNICs 2272(1)-(N) can transmit the callsto the NAT gateway 2238 that may transmit the calls to public Internet2254. In this example, the containers 2267(1)-(N) that can be accessedin real-time by the customer can be isolated from the control plane VCN2216 and can be isolated from other entities contained in the data planeVCN 2218. The containers 2267(1)-(N) may also be isolated from resourcesfrom other customers.

In other examples, the customer can use the containers 2267(1)-(N) tocall cloud services 2256. In this example, the customer may run code inthe containers 2267(1)-(N) that requests a service from cloud services2256. The containers 2267(1)-(N) can transmit this request to thesecondary VNICs 2272(1)-(N) that can transmit the request to the NATgateway that can transmit the request to public Internet 2254. PublicInternet 2254 can transmit the request to LB subnet(s) 2222 contained inthe control plane VCN 2216 via the Internet gateway 2234. In response todetermining the request is valid, the LB subnet(s) can transmit therequest to app subnet(s) 2226 that can transmit the request to cloudservices 2256 via the service gateway 2236.

It should be appreciated that IaaS architectures 1900, 2000, 2100, 2200depicted in the figures may have other components than those depicted.Further, the embodiments shown in the figures are only some examples ofa cloud infrastructure system that may incorporate an embodiment of thedisclosure. In some other embodiments, the IaaS systems may have more orfewer components than shown in the figures, may combine two or morecomponents, or may have a different configuration or arrangement ofcomponents.

In certain embodiments, the IaaS systems described herein may include asuite of applications, middleware, and database service offerings thatare delivered to a customer in a self-service, subscription-based,elastically scalable, reliable, highly available, and secure manner. Anexample of such an IaaS system is the Oracle Cloud Infrastructure (OCI)provided by the present assignee.

FIG. 23 illustrates an example computer system 2300, in which variousembodiments may be implemented. The system 2300 may be used to implementany of the computer systems described above. As shown in the figure,computer system 2300 includes a processing unit 2304 that communicateswith a number of peripheral subsystems via a bus subsystem 2302. Theseperipheral subsystems may include a processing acceleration unit 2306,an I/O subsystem 2308, a storage subsystem 2318 and a communicationssubsystem 2324. Storage subsystem 2318 includes tangiblecomputer-readable storage media 2322 and a system memory 2310.

Bus subsystem 2302 provides a mechanism for letting the variouscomponents and subsystems of computer system 2300 communicate with eachother as intended. Although bus subsystem 2302 is shown schematically asa single bus, alternative embodiments of the bus subsystem may utilizemultiple buses. Bus subsystem 2302 may be any of several types of busstructures including a memory bus or memory controller, a peripheralbus, and a local bus using any of a variety of bus architectures. Forexample, such architectures may include an Industry StandardArchitecture (ISA) bus, Micro Channel Architecture (MCA) bus, EnhancedISA (EISA) bus, Video Electronics Standards Association (VESA) localbus, and Peripheral Component Interconnect (PCI) bus, which can beimplemented as a Mezzanine bus manufactured to the IEEE P1386.1standard.

Processing unit 2304, which can be implemented as one or more integratedcircuits (e.g., a conventional microprocessor or microcontroller),controls the operation of computer system 2300. One or more processorsmay be included in processing unit 2304. These processors may includesingle core or multicore processors. In certain embodiments, processingunit 2304 may be implemented as one or more independent processing units2332 and/or 2334 with single or multicore processors included in eachprocessing unit. In other embodiments, processing unit 2304 may also beimplemented as a quad-core processing unit formed by integrating twodual-core processors into a single chip.

In various embodiments, processing unit 2304 can execute a variety ofprograms in response to program code and can maintain multipleconcurrently executing programs or processes. At any given time, some orall of the program code to be executed can be resident in processor(s)2304 and/or in storage subsystem 2318. Through suitable programming,processor(s) 2304 can provide various functionalities described above.Computer system 2300 may additionally include a processing accelerationunit 2306, which can include a digital signal processor (DSP), aspecial-purpose processor, and/or the like.

I/O subsystem 2308 may include user interface input devices and userinterface output devices. User interface input devices may include akeyboard, pointing devices such as a mouse or trackball, a touchpad ortouch screen incorporated into a display, a scroll wheel, a click wheel,a dial, a button, a switch, a keypad, audio input devices with voicecommand recognition systems, microphones, and other types of inputdevices. User interface input devices may include, for example, motionsensing and/or gesture recognition devices such as the Microsoft Kinect®motion sensor that enables users to control and interact with an inputdevice, such as the Microsoft Xbox® 360 game controller, through anatural user interface using gestures and spoken commands. Userinterface input devices may also include eye gesture recognition devicessuch as the Google Glass® blink detector that detects eye activity(e.g., ‘blinking’ while taking pictures and/or making a menu selection)from users and transforms the eye gestures as input into an input device(e.g., Google Glass®). Additionally, user interface input devices mayinclude voice recognition sensing devices that enable users to interactwith voice recognition systems (e.g., Siri® navigator), through voicecommands.

User interface input devices may also include, without limitation, threedimensional (3D) mice, joysticks or pointing sticks, gamepads andgraphic tablets, and audio/visual devices such as speakers, digitalcameras, digital camcorders, portable media players, webcams, imagescanners, fingerprint scanners, barcode reader 3D scanners, 3D printers,laser rangefinders, and eye gaze tracking devices. Additionally, userinterface input devices may include, for example, medical imaging inputdevices such as computed tomography, magnetic resonance imaging,position emission tomography, or medical ultrasonography devices. Userinterface input devices may also include, for example, audio inputdevices such as MIDI keyboards, digital musical instruments and thelike.

User interface output devices may include a display subsystem, indicatorlights, or non-visual displays such as audio output devices, etc. Thedisplay subsystem may be a cathode ray tube (CRT), a flat-panel device,such as that using a liquid crystal display (LCD) or plasma display, aprojection device, a touch screen, and the like. In general, use of theterm “output device” is intended to include all possible types ofdevices and mechanisms for outputting information from computer system2300 to a user or other computer. For example, user interface outputdevices may include, without limitation, a variety of display devicesthat visually convey text, graphics and audio/video information such asmonitors, printers, speakers, headphones, automotive navigation systems,plotters, voice output devices, and modems.

Computer system 2300 may comprise a storage subsystem 2318 thatcomprises software elements, shown as being currently located within asystem memory 2310. System memory 2310 may store program instructionsthat are loadable and executable on processing unit 2304, as well asdata generated during the execution of these programs.

Depending on the configuration and type of computer system 2300, systemmemory 2310 may be volatile (such as random access memory (RAM)) and/ornon-volatile (such as read-only memory (ROM), flash memory, etc.). TheRAM typically contains data and/or program modules that are immediatelyaccessible to and/or presently being operated and executed by processingunit 2304. In some implementations, system memory 2310 may includemultiple different types of memory, such as static random access memory(SRAM) or dynamic random access memory (DRAM). In some implementations,a basic input/output system (BIOS), containing the basic routines thathelp to transfer information between elements within computer system2300, such as during start-up, may typically be stored in the ROM. Byway of example, and not limitation, system memory 2310 also illustratesapplication programs 2312, which may include client applications, Webbrowsers, mid-tier applications, relational database management systems(RDBMS), etc., program data 2314, and an operating system 2316. By wayof example, operating system 2316 may include various versions ofMicrosoft Windows®, Apple Macintosh®, and/or Linux operating systems, avariety of commercially available UNIX® or UNIX-like operating systems(including without limitation the variety of GNU/Linux operatingsystems, the Google Chrome® OS, and the like) and/or mobile operatingsystems such as iOS, Windows® Phone, Android® OS, BlackBerry® 23 OS, andPalm® OS operating systems.

Storage subsystem 2318 may also provide a tangible computer-readablestorage medium for storing the basic programming and data constructsthat provide the functionality of some embodiments. Software (programs,code modules, instructions) that, when executed by a processor, providesthe functionality described above may be stored in storage subsystem2318. These software modules or instructions may be executed byprocessing unit 2304. Storage subsystem 2318 may also provide arepository for storing data used in accordance with the presentdisclosure.

Storage subsystem 2300 may also include a computer-readable storagemedia reader 2320 that can further be connected to computer-readablestorage media 2322. Together and, optionally, in combination with systemmemory 2310, computer-readable storage media 2322 may comprehensivelyrepresent remote, local, fixed, and/or removable storage devices plusstorage media for temporarily and/or more permanently containing,storing, transmitting, and retrieving computer-readable information.

Computer-readable storage media 2322 containing code, or portions ofcode, can also include any appropriate media known or used in the art,including storage media and communication media, such as, but notlimited to, volatile and non-volatile, removable and non-removable mediaimplemented in any method or technology for storage and/or transmissionof information. This can include tangible computer-readable storagemedia such as RAM, ROM, electronically erasable programmable ROM(EEPROM), flash memory or other memory technology, CD-ROM, digitalversatile disk (DVD), or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or other tangible computer readable media. This can also includenontangible computer-readable media, such as data signals, datatransmissions, or any other medium which can be used to transmit thedesired information and which can be accessed by computing system 2300.

By way of example, computer-readable storage media 2322 may include ahard disk drive that reads from or writes to non-removable, nonvolatilemagnetic media, a magnetic disk drive that reads from or writes to aremovable, nonvolatile magnetic disk, and an optical disk drive thatreads from or writes to a removable, nonvolatile optical disk such as aCD ROM, DVD, and Blu-Ray® disk, or other optical media.Computer-readable storage media 2322 may include, but is not limited to,Zip® drives, flash memory cards, universal serial bus (USB) flashdrives, secure digital (SD) cards, DVD disks, digital video tape, andthe like. Computer-readable storage media 2322 may also includesolid-state drives (SSD) based on non-volatile memory such asflash-memory based SSDs, enterprise flash drives, solid state ROM, andthe like, SSDs based on volatile memory such as solid state RAM, dynamicRAM, static RAM, DRAM-based SSDs, magnetoresistive RAM (MRAM) SSDs, andhybrid SSDs that use a combination of DRAM and flash memory based SSDs.The disk drives and their associated computer-readable media may providenon-volatile storage of computer-readable instructions, data structures,program modules, and other data for computer system 2300.

Communications subsystem 2324 provides an interface to other computersystems and networks. Communications subsystem 2324 serves as aninterface for receiving data from and transmitting data to other systemsfrom computer system 2300. For example, communications subsystem 2324may enable computer system 2300 to connect to one or more devices viathe Internet. In some embodiments communications subsystem 2324 caninclude radio frequency (RF) transceiver components for accessingwireless voice and/or data networks (e.g., using cellular telephonetechnology, advanced data network technology, such as 3G, 4G or EDGE(enhanced data rates for global evolution), WiFi (IEEE 802.11 familystandards, or other mobile communication technologies, or anycombination thereof), global positioning system (GPS) receivercomponents, and/or other components. In some embodiments communicationssubsystem 2324 can provide wired network connectivity (e.g., Ethernet)in addition to or instead of a wireless interface.

In some embodiments, communications subsystem 2324 may also receiveinput communication in the form of structured and/or unstructured datafeeds 2326, event streams 2328, event updates 2330, and the like onbehalf of one or more users who may use computer system 2300.

By way of example, communications subsystem 2324 may be configured toreceive data feeds 2326 in real-time from users of social networksand/or other communication services such as Twitter® feeds, Facebook®updates, web feeds such as Rich Site Summary (RSS) feeds, and/orreal-time updates from one or more third party information sources.

Additionally, communications subsystem 2324 may also be configured toreceive data in the form of continuous data streams, which may includeevent streams 2328 of real-time events and/or event updates 2330, thatmay be continuous or unbounded in nature with no explicit end. Examplesof applications that generate continuous data may include, for example,sensor data applications, financial tickers, network performancemeasuring tools (e.g., network monitoring and traffic managementapplications), clickstream analysis tools, automobile trafficmonitoring, and the like.

Communications subsystem 2324 may also be configured to output thestructured and/or unstructured data feeds 2326, event streams 2328,event updates 2330, and the like to one or more databases that may be incommunication with one or more streaming data source computers coupledto computer system 2300.

Computer system 2300 can be one of various types, including a handheldportable device (e.g., an iPhone® cellular phone, an iPad® computingtablet, a PDA), a wearable device (e.g., a Google Glass® head-mounteddisplay), a PC, a workstation, a mainframe, a kiosk, a server rack, orany other data processing system.

In the foregoing description, for the purposes of explanation, specificdetails are set forth to provide a thorough understanding of examples ofthe disclosure. However, it will be apparent that various examples maybe practiced without these specific details. The ensuing descriptionprovides examples only and is not intended to limit the scope,applicability, or configuration of the disclosure. Rather, the ensuingdescription of the examples will provide those skilled in the art withan enabling description for implementing an example. It should beunderstood that various changes may be made in the function andarrangement of elements without departing from the spirit and scope ofthe disclosure as set forth in the appended claims. The figures anddescription are not intended to be restrictive. Circuits, systems,networks, processes, and other components may be shown as components inblock diagram form in order not to obscure the examples in unnecessarydetail. In other instances, well-known circuits, processes, algorithms,structures, and techniques may be shown without unnecessary detail inorder to avoid obscuring the examples. The teachings disclosed hereincan also be applied to various types of applications such as mobileapplications, non-mobile applications, desktop applications, webapplications, enterprise applications, and the like. Further, theteachings of this disclosure are not restricted to a particularoperating environment (e.g., operating systems, devices, platforms, andthe like), but instead can be applied to multiple different operatingenvironments.

Also, it is noted that individual examples may be described as a processwhich is depicted as a flowchart, a flow diagram, a data flow diagram, astructure diagram, or a block diagram. Although a flowchart may describethe operations as a sequential process, many of the operations may beperformed in parallel or concurrently. In addition, the order of theoperations may be rearranged. A process is terminated when itsoperations are completed, but the process could have additional stepsnot included in a figure. A process may correspond to a method, afunction, a procedure, a subroutine, a subprogram, and so on. When aprocess corresponds to a function, its termination may correspond to areturn of the function to the calling function or the main function.

The words “example” and “exemplary” are used herein to mean “serving asan example, instance, or illustration.” Any embodiment or designdescribed herein as “exemplary” or “example” is not necessarily to beconstrued as preferred or advantageous over other embodiments ordesigns.

The term “machine-readable storage medium” or “computer-readable storagemedium” includes, but is not limited to, portable or non-portablestorage devices, optical storage devices, and various other mediumscapable of storing, containing, or carrying instruction(s) and/or data.A machine-readable storage medium or computer-readable storage mediummay include a non-transitory medium in which data may be stored andwhich does not include carrier waves and/or transitory electronicsignals propagating wirelessly or over wired connections. Examples of anon-transitory medium may include, but are not limited to, a magneticdisk or tape, optical storage media such as compact disk (CD) or digitalversatile disk (DVD), flash memory, or memory or memory devices. Acomputer-program product may include code and/or machine-executableinstructions that may represent a procedure, a function, a subprogram, aprogram, a routine, a subroutine, a module, a software package, a class,or any combination of instructions, data structures, or programstatements. A code segment may be coupled to another code segment or ahardware circuit by passing and/or receiving information, data,arguments, parameters, or memory contents. Information, arguments,parameters, data, and so forth may be passed, forwarded, or transmittedvia any suitable means including memory sharing, message passing, tokenpassing, network transmission, and so forth.

Furthermore, examples may be implemented by hardware, software,firmware, middleware, microcode, hardware description languages, or anycombination thereof. When implemented in software, firmware, middleware,or microcode, the program code or code segments to perform the necessarytasks (e.g., a computer-program product) may be stored in amachine-readable medium. A processor(s) may perform the necessary tasks.Systems depicted in some of the figures may be provided in variousconfigurations. In some examples, the systems may be configured as adistributed system where one or more components of the system aredistributed across one or more networks in a cloud computing system.Where components are described as being “configured to” perform certainoperations, such configuration may be accomplished, for example, bydesigning electronic circuits or other hardware to perform theoperation, by programming or controlling electronic circuits (e.g.,microprocessors or other suitable electronic circuits) to perform theoperation, or any combination thereof.

Although specific embodiments of the disclosure have been described,various modifications, alterations, alternative constructions, andequivalents are also encompassed within the scope of the disclosure.Embodiments of the present disclosure are not restricted to operationwithin certain specific data processing environments, but are free tooperate within a plurality of data processing environments.Additionally, although embodiments of the present disclosure have beendescribed using a particular series of transactions and steps, it shouldbe apparent to those skilled in the art that the scope of the presentdisclosure is not limited to the described series of transactions andsteps. Various features and aspects of the above-described embodimentsmay be used individually or jointly.

Further, while embodiments of the present disclosure have been describedusing a particular combination of hardware and software, it should berecognized that other combinations of hardware and software are alsowithin the scope of the present disclosure. Embodiments of the presentdisclosure may be implemented only in hardware, or only in software, orusing combinations thereof. The various processes described herein canbe implemented on the same processor or different processors in anycombination. Accordingly, where components or modules are described asbeing configured to perform certain operations, such configuration canbe accomplished, e.g., by designing electronic circuits to perform theoperation, by programming programmable electronic circuits (such asmicroprocessors) to perform the operation, or any combination thereof.Processes can communicate using a variety of techniques including, butnot limited to, conventional techniques for inter-process communication,and different pairs of processes may use different techniques, or thesame pair of processes may use different techniques at different times.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense. It will, however, beevident that additions, subtractions, deletions, and other modificationsand changes may be made thereunto without departing from the broaderspirit and scope as set forth in the claims. Thus, although specificdisclosure embodiments have been described, these are not intended to belimiting. Various modifications and equivalents are within the scope ofthe following claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the disclosed embodiments (especially in thecontext of the following claims) are to be construed to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms (i.e., meaning“including, but not limited to,”) unless otherwise noted. The term“connected” is to be construed as partly or wholly contained within,attached to, or joined together, even if there is something intervening.Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate embodiments of the disclosure anddoes not pose a limitation on the scope of the disclosure unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe disclosure.

Disjunctive language such as the phrase “at least one of X, Y, or Z,”unless specifically stated otherwise, is intended to be understoodwithin the context as used in general to present that an item, term,etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y,and/or Z). Thus, such disjunctive language is not generally intended to,and should not, imply that certain embodiments require at least one ofX, at least one of Y, or at least one of Z to each be present.

Preferred embodiments of this disclosure are described herein, includingthe best mode known for carrying out the disclosure. Variations of thosepreferred embodiments may become apparent to those of ordinary skill inthe art upon reading the foregoing description. Those of ordinary skillshould be able to employ such variations as appropriate and thedisclosure may be practiced otherwise than as specifically describedherein. Accordingly, this disclosure includes all modifications andequivalents of the subject matter recited in the claims appended heretoas permitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed by the disclosure unless otherwise indicated herein.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

In the foregoing specification, aspects of the disclosure are describedwith reference to specific embodiments thereof, but those skilled in theart will recognize that the disclosure is not limited thereto. Variousfeatures and aspects of the above-described disclosure may be usedindividually or jointly. Further, embodiments can be utilized in anynumber of environments and applications beyond those described hereinwithout departing from the broader spirit and scope of thespecification. The specification and drawings are, accordingly, to beregarded as illustrative rather than restrictive.

What is claimed is:
 1. A method implemented by a computer system, themethod comprising: receiving, from a first network virtualization device(NVD), first information about an internet group management protocol(IGMP) response of a first compute instance, the first informationindicating that the first compute instance is to be added to a multicastgroup, wherein: the first compute instance is hosted on a host machineand belongs to a Layer 2 virtual network, the Layer 2 virtual network ishosted on a physical network and includes a plurality of computeinstances, a plurality of Layer 2 virtual network interfaces, and aplurality of layer 2 virtual switches, the physical network includes thefirst NVD and the host machine, the first NVD hosts a first Layer 2virtual network interface of the plurality of Layer 2 virtual networkinterfaces and a first Layer 2 virtual switch of the plurality of Layer2 virtual switches, and the first Layer 2 virtual network interface andthe first Layer 2 virtual switch are associated with the first computeinstance; receiving, from a second NVD, second information about an IGMPresponse of a second compute instance, the second information indicatingthat the second compute instance is to be added to the multicast group;generating, based on the first information and the second information,an IGMP table indicating that the first compute instance and the secondcompute instance are added to the multicast group; and sending at leasta first portion of the IGMP table to the second NVD, wherein the secondNVD hosts a second Layer 2 virtual network interface of the plurality ofLayer 2 virtual network interfaces and a second Layer 2 virtual switchof the plurality of Layer 2 virtual switches, and wherein the secondLayer 2 virtual network interface and the second Layer 2 virtual switchare associated with a second compute instance of the plurality ofcompute instances, wherein the first portion sent to the second NVDincludes a first indication that the first compute instance is added tothe multicast group and excludes a second indication that the secondcompute instance is added to the multicast group.
 2. The method of claim1, wherein the IGMP table is sent to the first NVD and the second NVD.3. The method of claim 1 further comprising: sending, to the first NVD,a request for an IGMP query, wherein the first IGMP response is receivedbased on the IGMP query by the first NVD.
 4. The method of claim 3further comprising: determining, based on configuration information ofthe Layer 2 virtual network, that the first Layer 2 virtual switch isassociated with the first compute instance is hosted by the first NVD,wherein the request is sent to the first NVD based on the determiningthat the first Layer 2 virtual switch is associated with the firstcompute instance is hosted by the first NVD.
 5. The method of claim 1further comprising: receiving, from the first NVD, third informationindicating that the first compute instance is to be removed from themulticast group; generating, based on the third information, an updateto the IGMP table, the update indicating that the first compute instanceis removed from the multicast group; and sending, to the second NVD, atleast the update.
 6. The method of claim 5, wherein the update isfurther sent to another NVD but not the first NVD.
 7. A networkvirtualization device comprising: one or more processors, and one ormore computer-readable storage media storing instructions that, uponexecution by the one or more processors, configure the networkvirtualization device to: host a first Layer 2 virtual network interfaceand a first Layer 2 virtual switch that belong to a Layer 2 virtualnetwork, wherein: the first Layer 2 virtual network interface and thefirst Layer 2 virtual switch are associated with a first computeinstance that belongs to the Layer 2 virtual network, the first computeinstance is hosted on a host machine of a physical network thatcomprises the network virtualization device, the host machine and thenetwork virtualization device being communicatively coupled, and theLayer 2 virtual network is hosted on the physical network and comprisesa plurality of compute instances, a plurality of Layer 2 virtual networkinterfaces, and a plurality of Layer 2 virtual switches; send, to thefirst compute instance, an internet group management protocol (IGMP)query; receive an IGMP response of the first compute instance, the IGMPresponse indicating that the first compute instance is to be added to amulticast group; receive, from a computer system, at least a portion ofan IGMP table, wherein the IGMP table is generated based on firstinformation indicating that the first compute instance is to be added tothe multicast group and second information indicating that a secondcompute instance of the plurality of compute instances is added to themulticast group, wherein the second compute instance is associated witha second Layer 2 virtual network interface and a second Layer 2 virtualswitch that are hosted by a second network virtualization device; andstore a local IGMP table based on the IGMP response of the first computeinstance and the portion of the IGMP table received from the computersystem, wherein the portion excludes a first indication that the firstcompute instance is added to the multicast group, and wherein the localIGMP table includes the first indication.
 8. The network virtualizationdevice of claim 7, wherein the execution of the instructions furtherconfigures the network virtualization device to send first informationabout the IGMP response to the computer system, the first informationindicating that the first compute instance is to be added to themulticast group.
 9. The network virtualization device of claim 8,wherein the execution of the instructions further configures the networkvirtualization device to receive, from the computer system, a requestfor the IGMP query, wherein the IGMP query is sent based on the request.10. The network virtualization device of claim 8, wherein the executionof the instructions further configures the network virtualization deviceto: receive a frame of the first compute instance; determine, based onthe local IGMP table, that the frame is to be replicated and sent to thesecond compute instance; and send a replicated frame destined to thesecond compute instance.
 11. One or more computer-readable storage mediastoring instructions that, upon execution on a network virtualizationdevice, cause the network virtualization device to perform operationscomprising: hosting a first Layer 2 virtual network interface and afirst Layer 2 virtual switch that belong to a Layer 2 virtual network,wherein: the first Layer 2 virtual network interface and the first Layer2 virtual switch are associated with a first compute instance thatbelongs to the Layer 2 virtual network, the first compute instance ishosted on a host machine of a physical network that comprises thenetwork virtualization device, the host machine and the networkvirtualization device being communicatively coupled, and the Layer 2virtual network is hosted on the physical network and comprises aplurality of compute instances, a plurality of Layer 2 virtual networkinterfaces, and a plurality of Layer 2 virtual switches; sending, to thefirst compute instance, a first internet group management protocol(IGMP) query; receiving a first IGMP response of the first computeinstance, the first IGMP response indicating that the first computeinstance is to be added to a multicast group; receiving, from a computersystem, at least a portion of an IGMP table, wherein the IGMP table isgenerated based on first information indicating that the first computeinstance is to be added to the multicast group and second informationindicating that a second compute instance of the plurality of computeinstances is added to the multicast group, wherein the second computeinstance is associated with a second Layer 2 virtual network interfaceand a second Layer 2 virtual switch that are hosted by a second networkvirtualization device; and storing a local IGMP table based on the IGMPresponse of the first compute instance and the portion of the IGMP tablereceived from the computer system, wherein the portion excludes a firstindication that the first compute instance is added to the multicastgroup, and wherein the local IGMP table includes the first indication.12. The one or more computer-readable storage media of claim 11, furthercomprising sending first information about the first IGMP response tothe computer system, the first information indicating that the firstcompute instance is to be added to the multicast group.
 13. The one ormore computer-readable storage media of claim 12, further comprising:sending, to the first compute instance, a second IGMP query; andreceiving a second IGMP response of the first compute instance, whereinthe second IGMP response indicates that the first compute instance is tobe removed from the multicast group.
 14. The one or morecomputer-readable storage media of claim 13, further comprising updatingthe local IGMP table to indicate that the first compute instance isremoved from the multicast group.
 15. The one or more computer-readablestorage media of claim 13, further comprising sending, to the computersystem, an update indicating that the first compute instance is to beremoved from the multicast group.
 16. The method of claim 1, wherein alocal IGMP table of the second NVD is updated based at least in part onthe first portion.
 17. The method of claim 1, further comprising sendingat least a second portion of the IGMP table to the first NVD.
 18. Thenetwork virtualization device of claim 7, wherein the execution of theinstructions further configures the network virtualization device to:send, to the first compute instance, a second IGMP query; and receive asecond IGMP response of the first compute instance, wherein the secondIGMP response indicates that the first compute instance is to be removedfrom the multicast group.
 19. The network virtualization device of claim18, wherein the execution of the instructions further configures thenetwork virtualization device to update the local IGMP table to indicatethat the first compute instance is removed from the multicast group. 20.The method of claim 17, wherein the second portion sent to the first NVDexcludes a first indication that the first compute instance is added tothe multicast group and includes a second indication that the secondcompute instance is added to the multicast group.